System and method of tissue therapy using acoustic dose management

Abstract

A tissue treatment system may include a catheter having a distal portion on which an ultrasonic transducer is located, an excitation source that provides energy to the ultrasonic transducer, and a controller. At least the distal portion of the catheter is insertable into a segment of a body cavity having a diameter within a diameter range having a lower subrange and an upper subrange. The controller controls the excitation source to cause the ultrasonic transducer to emit at least a first amount of acoustic energy and a second amount of acoustic energy greater than the first amount of acoustic energy. The controller controls the excitation source to cause the ultrasonic transducer to emit the first amount of acoustic energy into a body cavity having a diameter within the lower subrange and to emit the second amount of acoustic energy into a body cavity having a diameter within the upper subrange.

Description

[Technical Field]

[0001] [Priority] This application claims priority to U.S. Provisional Patent Application No. 63 / 502,075, filed on 12 May 2023, entitled “System and Method for Tissue Therapy Using Acoustic Dose Control.” This document is incorporated herein by reference in its entirety to provide continuity of disclosure.

[0002] [Technical field] This application relates, as a whole, to minimally invasive devices, systems, and methods for delivering energy to a targeted anatomical location in a subject, and more specifically, to catheter-based intraluminal devices, systems, and methods configured to deliver ultrasound energy to treat tissues such as nerve tissue. [Background technology]

[0003] According to the Centers for Disease Control and Prevention (CDC), approximately one in three adults suffers from hypertension, also known as hypertension. If left untreated, hypertension can lead to kidney disease, arrhythmias, and heart failure. In recent years, the treatment of hypertension has focused on interventional approaches to inactivate the renal nerves surrounding the renal arteries. Autonomic nerves tend to run along blood vessels towards the organs they supply. A catheter can reach specific structures close to the body cavity through which the catheter moves, such as the renal nerves. Thus, a catheter-based system can deliver energy from within the lumen to inactivate the renal nerves. [Overview of the project]

[0004] An example of a tissue treatment system may include a catheter having a distal portion on which an ultrasonic transducer is located, an excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, and a controller communicatively coupled to the excitation source. Here, the catheter may be configured such that at least the distal portion of the catheter is insertable into a segment of a body cavity having a diameter within a specified diameter range, the diameter range may have a lower sub-range and an upper sub-range, the controller may be configured to control the excitation source such that the ultrasonic transducer can emit two different amounts of acoustic energy, the two different amounts of acoustic energy may include a first amount of acoustic energy and a second amount of acoustic energy greater than the first amount of acoustic energy, and the controller may be configured to control the excitation source such that the ultrasonic transducer emits the first amount of acoustic energy into a body cavity having a diameter within the lower sub-range and the second amount of acoustic energy into a body cavity having a diameter within the upper sub-range.

[0005] In one example of how a tissue therapy system operates, the tissue therapy system comprises a catheter including a distal portion on which an ultrasonic transducer is located, an excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, and a controller communicatively coupled to the excitation source, wherein at least the distal portion of the catheter is insertable into a segment of a body cavity having a diameter within a specified diameter range, the diameter range may have a lower sub-range and an upper sub-range, and the controller may be configured to control the excitation source such that the ultrasonic transducer emits two different amounts of acoustic energy, the two different amounts of acoustic energy may include a first amount of acoustic energy and a second amount of acoustic energy greater than the first amount of acoustic energy. Furthermore, one example of the operating method may include the following steps performed by the controller, namely, controlling the excitation source by using the ultrasonic transducer to selectively emit a first amount of acoustic energy when the diameter of the segment of the body cavity to be treated is within the lower sub-range, and selectively emitting a second amount of acoustic energy when the diameter of the segment of the body cavity to be treated is within the upper sub-range.

[0006] An example of a tissue treatment system may comprise a catheter including a distal portion on which an ultrasonic transducer is located, an excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, and a controller communicatively coupled to the excitation source, wherein at least the distal portion of the catheter may be insertable into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm, and the controller may be configured to control the excitation source such that the ultrasonic transducer emits only two different amounts of acoustic energy, the two different amounts of acoustic energy may include a first amount of acoustic energy when the diameter of the segment of the body cavity is within a lower sub-range of the specified diameter range, and a second amount of acoustic energy greater than the first amount of acoustic energy when the diameter of the segment of the body cavity is within an upper sub-range of the specified diameter range.

[0007] An example of how to use a tissue treatment system comprising a catheter including a distal portion on which an ultrasonic transducer is located may include the steps of: inserting the distal portion of the catheter into a segment of a body cavity having a diameter within the specified diameter range of at least 4 mm so that the ultrasonic transducer is located within the segment of the body cavity having a diameter within the specified diameter range of at least 4 mm; and, when the diameter of the segment of the body cavity is within the specified diameter range of at least 4 mm, causing the ultrasonic transducer to emit approximately the same amount of acoustic energy.

[0008] An example of how to use a tissue treatment system comprising a catheter including a distal portion on which an ultrasonic transducer is located may include the steps of: inserting the distal portion of the catheter into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm so that the ultrasonic transducer is located within the segment of the body cavity having a diameter within the specified diameter range of at least 4 mm; receiving input in a controller associated with the ultrasonic transducer whether the diameter of the segment of the body cavity on which the ultrasonic transducer is located is within a lower sub-range of the specified diameter range or within an upper sub-range of the specified diameter range; causing the ultrasonic transducer to emit a first amount of acoustic energy upon receiving input that the diameter of the segment of the body cavity is within the lower sub-range of the specified diameter range; and causing the ultrasonic transducer to emit a second amount of acoustic energy greater than the first amount of acoustic energy upon receiving input that the diameter of the segment of the body cavity is within the upper sub-range of the specified diameter range.

[0009] An example of a tissue therapy system may include a catheter having a distal portion configured to deliver neuromodulatory energy to a segment of a body cavity, an excitation source configured to selectively provide neuromodulatory energy to the catheter, and a controller communicatively coupled to the excitation source, wherein the controller may be configured to control the excitation source such that the catheter emits approximately the same amount of neuromodulatory energy when the diameter of the segment of the body cavity is within a first specified diameter range of at least 4 mm.

[0010] Novel features of this disclosure are specifically described in the following claims. A better understanding of the features and advantages of this disclosure will be obtained by referring to the following detailed description and accompanying drawings illustrating exemplary embodiments in which the principles of this disclosure are utilized. [Brief explanation of the drawing]

[0011] [Figure 1]FIG. 1 is a perspective view of a tissue treatment system according to one embodiment.

[0012] [Figure 2A] FIG. 2A is a side view of selected components of the tissue treatment system of FIG. 1 according to one embodiment.

[0013] [Figure 2B] FIG. 2B is a side view of selected components of the tissue treatment system of FIG. 1 according to one embodiment.

[0014] [Figure 3] FIG. 3 is a perspective view of selected components of the tissue treatment system of FIG. 1 inserted into a body cavity according to one embodiment.

[0015] [Figure 4] FIG. 4 is a longitudinal cross-sectional view of the distal region of a tissue treatment system according to one embodiment.

[0016] [Figure 5] FIG. 5 is a side view of a tissue treatment system having a compliant balloon inflated to a first inflation diameter according to one embodiment.

[0017] [Figure 6] FIG. 6 is a side view of a tissue treatment system having a compliant balloon inflated to a second inflation diameter according to one embodiment.

[0018] [Figure 7] FIG. 7 is a graph of the balloon pressure curve of a balloon inflated according to a pressure limit approach according to one embodiment.

[0019] [Figure 8A] FIG. 8A is a side view of a balloon having wrinkles when inflated smaller than its nominal inflation diameter according to one embodiment.

[0020] [Figure 8B] Figure 8B is a perspective view of a balloon with a spiral fold when inflated to a size smaller than its nominal expansion diameter, according to one embodiment.

[0021] [Figure 8C] Figure 8C is a perspective view of a balloon with longitudinal folds, according to one embodiment, when inflated to a size smaller than its nominal expansion diameter.

[0022] [Figure 8D] Figure 8D is a cross-sectional view of a balloon with longitudinal folds, according to one embodiment, when inflated to a size smaller than its nominal expansion diameter.

[0023] [Figure 8E] Figure 8E is a perspective view of a balloon with a spiral fold when inflated to a size smaller than its nominal expansion diameter, according to one embodiment.

[0024] [Figure 8F] Figure 8F is a cross-sectional view of a balloon with a spiral fold when inflated to a size smaller than its nominal expansion diameter, according to one embodiment.

[0025] [Figure 9] Figure 9 is a graph of the balloon pressure curve of a compliant balloon inflated according to a hybrid inflation approach according to one embodiment.

[0026] [Figure 10] Figure 10 shows illustrative details of a fluid supply subsystem according to one embodiment.

[0027] [Figure 11A] Figure 11A shows illustrative details of a controller according to one embodiment.

[0028] [Figure 11B] Figure 11B shows illustrative details of an ultrasonic excitation source introduced in Figure 11A according to one embodiment.

[0029] [Figure 12A] Figure 12A is a graph of acoustic penetration power against cavity size, corresponding to an exemplary implementation of a single-power embodiment for treating target tissue according to one embodiment.

[0030] [Figure 12B] Figure 12B is a graph of acoustic penetration power against cavity size, corresponding to another exemplary implementation of a single-power embodiment for treating target tissue according to one embodiment.

[0031] [Figure 13A] Figure 13A is a graph of acoustic penetration power against cavity size, corresponding to an exemplary implementation of a two-power embodiment for treating target tissue according to one embodiment.

[0032] [Figure 13B] Figure 13B is a graph of acoustic penetration power against cavity size, corresponding to another exemplary implementation of a two-power embodiment for treating target tissue.

[0033] [Figure 13C] Figure 13C is a graph of acoustic penetration power against cavity size, corresponding to yet another exemplary implementation of a two-power embodiment for treating target tissue.

[0034] [Figure 14] Figure 14 shows an exemplary graphical user interface (GUI) that allows the user to specify whether the diameter of a body cavity is within a lower sub-range of a specified diameter range or within an upper sub-range of a specified diameter range. This GUI may be used in a two-power embodiment.

[0035] [Figure 15]Figure 15 is a high-level flowchart summarizing a single-power method for use in a tissue treatment system with a catheter that includes a distal portion where an ultrasound transducer is located.

[0036] [Figure 16] Figure 16 is a high-level flowchart summarizing a two-power method for use in a tissue treatment system with a catheter that includes a distal portion where an ultrasound transducer is located. [Modes for carrying out the invention]

[0037] In a particular embodiment, the tissue treatment system comprises a catheter, an excitation source, and a controller. The catheter includes a distal portion on which an ultrasonic transducer is located. The catheter is configured to be insertable into a body cavity having a diameter within a specified diameter range, at least 4 mm in the distal portion of the catheter. The excitation source is configured to selectively supply energy to the ultrasonic transducer of the catheter. The controller is communicatively coupled to the excitation source.

[0038] In some embodiments, the controller of the tissue treatment system is configured to control the excitation source such that when the diameter of the body cavity segment is within a specified diameter range of at least 4 mm, for example, about 3.0 mm to about 8.0 mm, but not limited thereto, the ultrasonic transducer emits approximately the same amount of acoustic energy.

[0039] In other embodiments, the controller of the tissue treatment system is configured to control the excitation source such that an ultrasonic transducer emits only two different amounts of acoustic energy. These acoustic energies include a first amount of acoustic energy when the diameter of the body cavity segment is within a lower sub-range of a specified diameter range (e.g., about 3.0 mm to about 4.9 mm), and a second amount of acoustic energy greater than the first amount of acoustic energy when the diameter of the body cavity segment is within an upper sub-range of the specified diameter range (e.g., about 5.0 mm to about 8.0 mm).

[0040] Some embodiments also include methods using the tissue treatment systems described in the summary section above.

[0041] A single-power method for use in a tissue treatment system comprising a catheter including a distal portion on which an ultrasonic transducer is positioned comprises the steps of: inserting the distal portion of the catheter into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm, thereby positioning the ultrasonic transducer within the segment of the body cavity having a diameter within a specified diameter range of at least 4 mm; and causing the ultrasonic transducer to radiate approximately the same amount of acoustic energy when the diameter of the segment of the body cavity is within the specified diameter range of at least 4 mm.

[0042] A two-power method for use in a tissue treatment system comprising a catheter including a distal portion on which an ultrasonic transducer is located comprises the steps of inserting the distal portion of the catheter into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm, thereby positioning the ultrasonic transducer within the segment of the body cavity having a diameter within a specified diameter range of at least 4 mm. The method also comprises the steps of determining whether the diameter of the segment of the body cavity on which the ultrasonic transducer is located is within a lower sub-range or an upper sub-range of the specified diameter range. The method further comprises the steps of causing the ultrasonic transducer to emit a first amount of acoustic energy when it is determined that the diameter of the segment of the body cavity on which the ultrasonic transducer is located is within a lower sub-range of the specified diameter range, and causing the ultrasonic transducer to emit a second amount of acoustic energy (greater than the first amount of acoustic energy) when it is determined that the diameter of the segment of the body cavity on which the ultrasonic transducer is located is within an upper sub-range of the specified diameter range.

[0043] This description is not intended to exhaustively enumerate all aspects of the Disclosure. The Disclosure is intended to be implemented in any suitable combination of the various aspects summarized in the Summary section above, the various aspects disclosed in the remainder of this Specification, and the various aspects specifically indicated in the Claims. Such combinations have special advantages not specifically described in the Summary section above.

[0044] In certain embodiments, a tissue therapy system equipped with a compliant balloon and a method of using the tissue therapy system are described. The tissue therapy system may be an acoustic-based tissue therapy system, such as an ultrasound-based tissue therapy system, used to heat and treat tissue within a targeted anatomical region by delivering unfocused ultrasound energy radially outward. The unfocused ultrasound energy may selectively target nerve tissue within an anatomical region and heat the nerve tissue to neuromodulate it (e.g., completely or partially ablate, necrotize, or stimulate the nerve tissue). Accordingly, the tissue therapy system may be used to neuromodulate renal nerves to treat hypertension, chronic kidney disease, atrial fibrillation, anxiety, depression, diabetes, sleep apnea, metabolic disorders, insulin resistance, heart failure, or other medical conditions. Alternatively, the tissue therapy system may be used for other purposes, such as treating the sympathetic nerves of the hepatic plexus in the hepatic artery, which are important for the treatment of diabetes, or treating the sympathetic nerves of the pulmonary artery for the treatment of pulmonary hypertension. In certain embodiments, the tissue therapy catheter is additionally or alternatively used for ablation of conduction tissue and / or neuromodulation / ablation of sympathetic nerves, such as in the pulmonary veins, to treat atrial fibrillation and / or other cardiac arrhythmias and / or hypertension. In certain embodiments, the tissue therapy catheter is additionally or alternatively used to treat autoimmune diseases and / or inflammatory diseases such as rheumatoid arthritis, sepsis, Crohn's disease, ulcerative colitis, and / or gastrointestinal motility disorders by neuromodulating sympathetic nerves in one or more of the splenic artery, celiac artery, upper mesenteric artery, or lower mesenteric artery. Therefore, referring to the system as a renal nerve removal system, or as one used for the treatment, e.g., neuromodulation, of renal nerve tissue, does not limit the invention.

[0045] In various embodiments, the description will be made with reference to the drawings. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and forms. To provide a complete understanding of the embodiments, the following description will include numerous specific details, such as specific forms, dimensions, and processes. In other examples, well-known processes and manufacturing techniques will not be described in particular detail, so as not to unnecessarily complicate the description. Throughout this specification, references such as “one embodiment” mean that the specific feature, structure, form, or characteristic described is included in at least one embodiment. Therefore, when the phrase “one embodiment” is used in various places in this specification, it does not necessarily refer to the same embodiment. Furthermore, specific feature, structure, form, or characteristic may be combined in any suitable manner in one or more embodiments.

[0046] Throughout this description, the use of relative terminology may indicate relative location or direction. For example, “distal” may refer to a first direction along the longitudinal axis of the tissue treatment system. Similarly, “proximal” may refer to a second direction opposite to the first. However, such terminology is provided to establish a relative reference frame and is not intended to limit the use or direction of the tissue treatment system to the specific forms described in the various embodiments below.

[0047] Radial access catheters offer reduced pain during insertion, fewer complications such as bleeding and infection at the access site, and shorter overall treatment times. Patients may even be discharged on the same day as treatment. The catheter-based systems described below may provide a guide sheath and a compatible balloon configured for insertion via the radial vessel in the arm. For example, the balloon of system 100 may have a transverse profile of less than 5 French, less than 0.060 inches (0.1524 cm), and / or less than 0.058 inches (0.14732 cm). Furthermore, the balloon may have a transverse profile of 4 French.

[0048] The embodiments described herein can provide consistently safe and effective ultrasound ablation treatment. In certain embodiments, a balloon in which an ultrasound transducer is placed does not significantly attenuate the acoustic energy from the transducer and does not significantly interfere with the acoustic energy radiated by the transducer. For example, in certain embodiments, the balloon is provided composed of a material and selective thickness that interferes only minimally with the energy transfer of the transducer. In other embodiments, the balloon is specifically designed to attenuate the acoustic energy radiated from the transducer so that less acoustic energy is delivered to the tissue under treatment when the balloon and transducer are positioned in a relatively small diameter body cavity segment compared to when the balloon and transducer are positioned in a relatively large diameter body cavity segment. Such embodiments help to deliver an appropriate amount of acoustic energy to the tissue under treatment using a balloon and will be described in further detail below.

[0049] This specification provides a tissue treatment system comprising a catheter having a compliant medical balloon configured for use in a wide range of vascular lumen diameters. In one embodiment, the compliant balloon is mounted on a catheter shaft and has an interior for housing an ultrasonic transducer. The compliant balloon may be formed from and may have a structure such that it can expand to juxtapose with a wide range of body lumens. For example, the compliant balloon may be formed from a polyether-based thermoplastic polyurethane and may have an operating section having a predetermined linearity over a range of expansion diameters. The range of expansion diameters may include multiple diameters with a difference of at least 2 mm. For example, the first diameter may be in the range of 3.5 to 6 mm, for example 5 mm, and the second diameter may be in the range of 8 to 9 mm, for example 8.5 mm.

[0050] In certain embodiments, arterially restricting compliance balloons are provided. In certain arterially restricting embodiments, the balloon material is selected such that the balloon's folds (also called wrinkles) do not interfere with sonication. In certain arterially restricting embodiments, the balloon material is selected such that the balloon forms folds (wrinkles) in a predictable manner, and the energy profile may be adjusted so that the folds do not interfere with sonication of the transducer. In other embodiments, a compliant balloon material is selected and configured such that folds (wrinkles) occur in a predictable manner, and when the compliant balloon is partially inflated to a size smaller than its nominal balloon diameter, the folded balloon material at least partially attenuates a portion of the acoustic energy radiated by the transducer, thereby reducing the amount of acoustic energy passing through the balloon when the diameter of the body cavity segment is in a smaller diameter subset of a specified diameter range compared to when the diameter of the body cavity segment is in a larger diameter subset of a specified diameter range. More generally, the folds in the compliant balloon that exist when the compliant balloon is partially inflated and its diameter is smaller than the nominal balloon diameter of the compliant balloon are configured to attenuate more of the acoustic energy radiated by the ultrasonic transducer, thereby reducing the amount of acoustic energy passing through the compliant balloon 108 when the compliant balloon is adjacent to (juxtaposed with) a body cavity segment having a diameter within a smaller diameter subset of the specified diameter range (e.g., less than 5 mm) compared to when the compliant balloon is adjacent to (juxtaposed with) a body cavity segment having a diameter within a larger diameter subset of the specified diameter range (e.g., 5 mm or more).

[0051] As used herein, the inflated diameter refers to the outer diameter of the cross-sectional shape of the balloon passing through the center of the transducer. More specifically, a cross-section perpendicular to the central axis of the balloon intersects the balloon in its outer profile. The outer dimension (e.g., outer diameter) of this profile represents the inflated diameter of the balloon. In one embodiment, the outer diameter can be measured by inflating the balloon and measuring the outer dimension on the balloon surface radially outward from the transducer. For example, the balloon may be supported in free space, inflated to a predetermined inflation pressure, and the outer diameter of the inflated balloon may be measured using a measuring tool such as a laser caliper. The nominal inflated diameter of a balloon refers to the diameter of the balloon when it is inflated to a degree in which there are substantially no wrinkles or other folds in the balloon body and the balloon material has not yet been stretched.

[0052] A predetermined linearity of the working section of the balloon allows the transducer to be supported and centered within the target vessel. In one embodiment, this predetermined linearity includes the cylindricity of the working section being less than a predetermined threshold (e.g., 1 mm). Linearity may also be determined with respect to other geometric properties, such as the ratio of the radius of curvature of the working section to the length of the compliant balloon, or the ratio of the radius of curvature of the working section at different inflation diameters. A predetermined linearity of a compliant balloon may be advantageous in terms of tissue contact and transducer support compared to a typical compliant balloon that tends to have a spherical profile when inflated.

[0053] Referring to Figure 1, a perspective view of selected components of a tissue treatment system according to one embodiment is shown. The tissue treatment system 100 may be a catheter-based system. More specifically, the system 100 may include a catheter 102 that can be delivered intracavitary, for example, intravascular, to an anatomical region of a target of a subject. When positioned in this manner, the transducer of the system (Figure 2A) may be positioned within the anatomical structure of the target, for example, within a body cavity such as a blood vessel. As will be described later, the transducer may be an ultrasonic transducer that can be placed inside a medical balloon 108. The transducer may be activated to deliver non-focused ultrasonic energy radially outward, thereby appropriately heating and treating tissue within the anatomical region of the target. The transducer may be activated at a frequency, time, and energy level suitable for treating the targeted tissue.

[0054] The tissue treatment system 100 may include a catheter 102, a controller 104, and a connecting cable 106. The tissue treatment system 100 may further include a balloon 108, a reservoir 110, a cartridge 112, and a control mechanism such as a handheld remote controller. In certain embodiments, the controller 104 is connected to the catheter 102 via the cartridge 112 and the connecting cable 106. In certain embodiments, the controller 104 interfaces with the cartridge 112 to provide cooling fluid to the catheter 102 to inflate and deflate the balloon 108. The controller 104 may also be called a control unit 104.

[0055] In one embodiment, the catheter 102 may include a compliant balloon 108 configured to accommodate a range of target vessel sizes, as described later. The compliant balloon 108 may accommodate differences in vascular lumen diameter along the length of the artery, or differences between the left and right renal arteries. For example, the compliant balloon 108 may be configured to treat vessels with vascular lumen diameters of 3 to 9 mm. Thus, the compliant balloon 108 may reduce the need to use multiple different balloon catheters 102 for each procedure. Consequently, the balloon 108 may reduce the time and complexity of the procedure.

[0056] Referring to Figure 2A, a side view of selected components of the tissue treatment system of Figure 1 according to one embodiment is shown. The tissue treatment catheter 102 may include a distal region 202 and a proximal region 204. The catheter 102 may have a length depending on the therapeutic application. For example, in a particular embodiment suitable for renal nerve debridement by a femoral access delivery method, the catheter 102 may have an operating length of 80-90 cm, e.g., 85 cm (measured length from the distal tip of the catheter 102 to the proximal hub 240 of the catheter 102) during the femoral access delivery method. For example, in a particular embodiment suitable for renal nerve debridement by a radial access delivery method, the catheter 102 may have a relatively long operating length. More specifically, the operating length may be 150-160 cm, e.g., 155 cm. Furthermore, the total length of the catheter 102 for such applications may be longer, including the length of the cable extending to the electrical coupling 206. More specifically, the cable may have a length of approximately 305 cm from the proximal hub 240 to the electrical coupling 206.

[0057] The catheter 102 may have a profile suitable for accessing the renal artery through access points in the femur and radius. For example, the diameter of the catheter 102 may be 4 to 6 French, e.g., 5 French. This profile is partially facilitated by the catheter shaft 212 having an outer diameter in the range of 0.050 to 0.060 inches (e.g., 0.057 inches).

[0058] The distal region 202 of the tissue treatment system 100 may be part of a device that is advanced into a target anatomical structure, for example, into a target vessel having a vascular wall, to treat the target vessel. The distal region 202 may include a balloon 108 attached to a catheter shaft 212. The balloon 108 may be a compliant balloon having the characteristics described in detail below. For example, the balloon 108 may have a cylindrical shape that supports and centers the transducer 214 within a certain range of the vessel diameter, thereby contributing to uniform energy delivery.

[0059] The catheter shaft 212 may be an elongated tubular structure extending longitudinally from the proximal end to the distal end. The balloon 108 may be attached to and supported at the distal end of the catheter shaft 212. Furthermore, the ultrasonic transducer 214 may be attached to the catheter shaft 212 and housed within the balloon 108. Thus, the catheter shaft 212 facilitates the supply of cooling fluid to the balloon 108 and the supply of electrical energy to the transducer 214.

[0060] The catheter shaft 212 may include one or more lumens (Figure 4) that can be used as a fluid conduit, an electrical cable passage, a guidewire lumen, etc. In one embodiment, the catheter shaft 212 may include a guidewire lumen 213 that is shaped, sized, and otherwise configured to receive a guidewire. In one embodiment, the guidewire lumen 213 is a wire-through type guidewire lumen that extends from the distal tip of the catheter 102 through the entire length of the catheter shaft 212 to the exit port 250 of the proximal hub 240 of the catheter 102. As will be described later, the lumen of the catheter shaft 212 may also transmit inflation / cooling fluid from the proximal region 204 to the balloon 108 during balloon inflation.

[0061] In one embodiment, the transducer 214 is attached to the distal region 202 of the catheter shaft 212 inside the balloon 108. The transducer 214 may be an ultrasonic transducer 214 used to radiate energy toward the blood vessel wall. For example, the transducer 214 may radiate ultrasonic energy circumferentially, for example, 360 degrees, around the blood vessel wall. In one embodiment, an electrical cable 216 extends from the proximal region 204 to the distal region 202 and is connected to the transducer 214 to generate energy for radiation toward the target tissue.

[0062] The ultrasonic transducer 214 may include first and second electrodes positioned on either side of a cylindrical piezoelectric material such as lead zirconate titanate (PZT). To energize the transducer 214, a voltage is applied between the first and second electrodes at a frequency selected to cause the piezoelectric material to resonate, thereby generating vibrational energy that is radiated radially outward from the transducer 214. The transducer 214 is designed to provide an overall uniform and predictable radiation profile to minimize damage to surrounding non-target tissues. Furthermore, before, during, and after activation of the transducer 214, a cooling fluid is circulated through the balloon 108 to reduce heating of the inner wall of the body cavity and cool the transducer 214. In this way, the peak temperature achieved by the tissue within the cooling region can be kept lower than that of the tissue located outside the cooling region.

[0063] The proximal region 204 may include one or more connectors or couplings. These connectors or couplings may be electrically connected to the transducer 214 via the electrical cable 216. For example, the proximal region 204 may include one or more electrical couplings 206 connected to the proximal end of the electrical cable 216. The distal end of the electrical cable 216 may be connected to the transducer 214.

[0064] Catheter 102 can be connected to controller 104 by connecting its electrical coupling 206 to a connecting cable 106. The connecting cable 106 can be detachably connected to controller 104 and / or catheter 102 via a port on controller 104 and / or catheter 102. Thus, controller 104 can be used with multiple catheters 102 during a single procedure (surgery) by detaching the coupling of the first catheter, replacing the first catheter with the second catheter, and connecting the coupling of the second catheter to controller 104. In certain embodiments, for example, if only one catheter needs to be used during a single procedure (surgery), the connecting cable 106 can be permanently connected to controller 104.

[0065] In certain embodiments, the proximal region 204 of the catheter 102 may further include one or more fluid ports. For example, the proximal hub 240 may include a fluid inlet port 208 and a fluid outlet port 210 through which an expandable member (e.g., a balloon 108) can be fluidly coupled to a reservoir 110 (Figure 1). Thus, the reservoir 110 can supply cooling fluid to the balloon 108 through these fluid ports. The reservoir 110 may optionally be included with the controller 104 and may be attached to the outer housing of the controller 104, for example, as shown in Figure 1. Alternatively, the reservoir 110 may be provided separately.

[0066] Referring to Figure 2B, a side view of selected components of the tissue treatment system of Figure 1 according to one embodiment is shown. In one embodiment, the catheter 102 may have a rapid-replacement type guidewire lumen 213. More specifically, the guidewire lumen 213 may extend from the distal tip of the catheter 102 through a portion of the length of the catheter shaft 212 to the exit port 250 of the distal portion 202 of the catheter 102. For example, the distance from the distal tip to the rapid-replacement port 250 may be in the range of 20-30 cm, e.g., 23 cm. The proximal hub 240 shown in Figure 2B may differ from the proximal hub 240 shown in Figure 2A, considering that the exit port 250 may move from the proximal portion 204 to the distal portion 202. Other components of the rapid-replacement version of the catheter 102 may be similar to those of the wired version of the catheter 102, and therefore the description of the components shown in Figure 2A is applicable to similarly referenced components shown in Figure 2B.

[0067] Referring to Figure 3, a perspective view of additional selected components of the tissue therapy system of Figure 1 inserted into a body cavity according to one embodiment is shown. The tissue therapy system 100 can be inserted into a body cavity of a subject. For example, the distal region 202 of the catheter 102 of the tissue therapy system 100 can be advanced into a target vessel 302, for example, a blood vessel such as a renal artery. The target vessel 302 may have a plurality of nerves 304 in its outer layer, for example, the adventitia. In one embodiment, the tissue therapy system 100 includes a guidewire support tip 308 having a lumen connected to a guidewire lumen 213 of a catheter shaft 212. The support tip 308 can receive a guidewire 310 and allow the device to move along the guidewire 310 to a target anatomical structure.

[0068] When the distal region 202 is positioned within the lumen of the target vessel 302, the transducer 214 and balloon 108 (or other suitable expandable member) are positioned radially medial to the nerves 304. The transducer 214 may be partially or completely positioned inside the balloon 108. To inflate the balloon 108, it may be filled with an inflation fluid 306, such as a cooling fluid. When the balloon 108 is inflated with the inflation fluid 306, it may come into contact with the inner surface of the target vessel, such as the intima. Thus, the inflated balloon 108 may have an expansion diameter equal to the lumen diameter 320 of the target vessel 302, may be adjacent to the target vessel 302 (may be juxtaposed), and may center the transducer 214 within the target vessel 302.

[0069] In certain embodiments, a transducer 214 may be used to output an acoustic signal when the balloon 108 completely occludes the target lumen. The balloon 108 can be centered on the transducer 214 in the target lumen. In certain embodiments suitable for renal nerve decompression, for example, the balloon 108 may be a compliant balloon 108, as described below, which can be inflated in the patient during the procedure at an operating pressure of about 1.4 atm to about 2 atm using an inflation fluid 306. The balloon 108 is sized for insertion into a target lumen, and when inserted into, for example, a renal artery, the balloon 108 may be selected to have an expanded size including one or more outer diameters of 3.5 mm, 4.2 mm, 5 mm, 6 mm, 7 mm, 8 mm, or 9 mm. The balloon 108 may have a burst strength of more than 45 psi.

[0070] In some embodiments, when the balloon 108 is filled with the expansion fluid 306 and inflated into the target vessel 302 under the control of the controller 104, the balloon wall of the balloon 108 may be substantially parallel to the outer surface of the transducer 214. Optionally, the balloon 108 may be sufficiently inflated to be adjacent to (juxtaposed with) the target vessel. For example, when inflated, the balloon 108 may at least partially contact the inner wall of the target vessel and thus be adjacent to (juxtaposed with) the inner wall of the target vessel. In other embodiments, the balloon 108 is configured not to contact the target vessel when expanded. The balloon 108 may be maintained at a specific size by, for example, pushing fluid into the balloon 108 via the inlet port 208 and withdrawing fluid from the balloon 108 at a specific flow rate via, for example, the outlet port 210. More specifically, the expansion fluid 306 may circulate within the balloon 108 to expand it.

[0071] Referring to Figure 4, a longitudinal cross-sectional view of the distal region of a tissue treatment system according to one embodiment is illustrated. In a particular embodiment, the diameter of the catheter shaft 212 may be about 1.8 mm. As previously stated, the catheter shaft 212 includes one or more thromboembolic lumens that can be used as a fluid conduit, a passage for an electrical cable or guidewire 310, etc. For example, the catheter shaft 212 may include a guidewire lumen 213 which is shaped, sized, and otherwise configured to receive a guidewire. The catheter shaft 212 may also include a cable lumen 401 for receiving an electrical cable (extending through the same shaft as the guidewire lumen 213), and / or a fluid lumen for transporting an expanding / cooling fluid (e.g., water, sterile water, saline, 5% dextrose (D5W), other liquids, other gases, etc.) to a fluid source (e.g., reservoir 110) located in the proximal region 204 of the catheter 102 outside the patient. The catheter shaft 212 may include one or more fluid channels 420 for moving fluid in and out of the balloon 108. For example, the fluid channels may include an inlet channel 403 for delivering inflation fluid 306 from the inlet port 208 to the balloon 108 under the control of the controller 104. Similarly, the fluid channels may include an outlet channel 405 for removing fluid from the balloon 108 to the outlet port 210. Thus, the inlet channel 403 and the outlet channel 405 are in fluid communication with the balloon 108 and circulate fluid through the balloon 108 at a selected flow rate to inflate the balloon 108. This flow rate also controls heat transfer between the balloon 108 and the blood vessel wall 303, reducing the possibility of tissue overheating during treatment. For example, this flow rate may provide active cooling of the first approximately 1 millimeter of tissue, preserving the integrity of, for example, the renal artery wall.

[0072] For example, in a particular embodiment suitable for renal nerve decompression, the guidewire 310 has a diameter of approximately 0.36 mm and a length of approximately 180 cm to approximately 300 cm, and is delivered using a 7-French guide catheter 102 having a minimum inner diameter of 2.06 mm and a length of less than approximately 80 cm. In a particular embodiment, a 6-French guide catheter 102 is used to deliver the guidewire 310. In a particular embodiment, the guide catheter 102 has a length of approximately 55 cm. In a particular embodiment, the guide catheter 102 has a length of approximately 85 cm, and a hemostatic valve is attached to the hub of the guide to continuously perfuse the guide and reduce the risk of thromboembolism. In a particular embodiment, the guidewire lumen 213 is positioned at the center of the catheter shaft 212 in order to center the transducer 214.

[0073] The ultrasonic transducer 214 may include a cylindrical tube 402 made of a piezoelectric material (e.g., lead zirconate titanate (PZT)), with an inner electrode 404 and an outer electrode 406 positioned along the inner and outer surfaces of the cylindrical tube 402, respectively. In a particular embodiment suitable for renal nerve debridement, for example, the piezoelectric material includes PZT-8 (Navy III). The raw PZT transducer 214 may be plated with layers of copper, nickel, and / or gold to create electrodes on the inner and outer surfaces of the cylindrical body. The application of alternating current between the inner electrode 404 and the outer electrode 406 causes the piezoelectric material to vibrate transversely to the longitudinal direction of the cylindrical tube 402, emitting ultrasonic waves radially (radially).

[0074] Furthermore, the transducer 214 is generally supported via a backing member or post 408. In certain embodiments, the backing member 408 includes stainless steel coated with nickel and gold, where nickel is used as a bonding material between the stainless steel and the gold plating. For example, in a particular embodiment suitable for renal nerve removal, the outer diameter of the transducer 214 is approximately 1.5 mm, the inner diameter of the transducer 214 is approximately 1 mm, and the transducer 214 has a length in the range of, for example, 3 to 9 mm, for example, a length of approximately 6 mm. The backing member 408 may extend from the distal end of the catheter shaft 214 to the support tip 308. For example, the distal end of the backing member 408 may be positioned within an adjacent opening in the support tip 308, and the proximal end of the backing member 408 may be movably coupled to the distal end of the catheter shaft 212 via an electrical cable. In other embodiments, a gap 410 exists between the distal end of the catheter shaft 212 and the backing member 408 that supports the transducer 214, and / or a gap exists between the backing member 408 and the support tip 308.

[0075] To allow liquid cooling along both the inner electrode 404 and the outer electrode 406, the backing member 408 may include one or more standoff assemblies 412. The standoff assembly 412 may define one or more annular openings 414 through which the cooling fluid can enter the space between the backing member 408 and the inner electrode 404. The backing member 408 may function as a fluid barrier between the expansion / cooling fluid circulating within the balloon 108 and the lumen of the backing member 408 that receives the guidewire 310. The standoff assembly 412 of the backing member 408 may be positioned along each end of the ultrasonic transducer 214 (separated by the main post body 416) to connect the cylindrical tube 402 of the ultrasonic transducer 214 to the backing member 408. The standoff assembly 412 may have a plurality of lugs, ribs, or mounting points that engage with the inner electrode 404 of the transducer 214. In certain embodiments, the multiple mounting points are soldered to the inner electrode 404 of the transducer 214. The number, dimensions, and arrangement of the multiple ribs may vary as desired or required. For example, a total of three ribs are arranged at approximately equal intervals and 120-degree angles to each other to define an annular opening 414. Through the annular opening 414, fluids and blood can enter the internal space of the cylindrical tube 402 between the inner electrode 404, which is positioned along the inner surface of the cylindrical tube 402, and the backing member 408. In certain embodiments, the maximum outer diameter of the standoff assembly is about 1 mm, the outer diameter of the main post body 416 is about 0.76 mm, and the inner diameter of the backing member 408 is about 0.56 mm.

[0076] The standoff assembly may be conductive in order to electrically couple the inner electrode 404 of the ultrasonic transducer 214 to the backing member 408. One or more conductors of the electrical cable may be electrically coupled to the backing member 408. Thus, when the controller 104 is activated, current can be delivered from the electrical cable to the inner electrode 404 of the ultrasonic transducer 214 via the backing member 408 and the standoff assembly, which advantageously eliminates the need to directly couple the electrical cable to the inner electrode 404 of the transducer 214.

[0077] In one embodiment, the backing member 408 may have an insulating tube (not shown) positioned along its inner surface to prevent or reduce the possibility of electrical conduction between the guidewire 310 and the backing member 408. The insulating tube may be made of a non-conductive material (e.g., a polymer such as polyimide). The insulating tube may extend from the distal end of the catheter 212 to the support tip 308 through the lumen of the backing member 408 within the transducer 214. The transducer 214 may be attached to the insulating tube and / or electrical cable. In this embodiment, the transducer 214 may be offset distally from the distal end of the catheter shaft 212 by a gap 410.

[0078] The catheter 102 may also include a hole 418 extending proximal from the distal end of the catheter shaft 212 into the catheter 102. The hole 418 may be sized and shaped to receive at least a portion of the backing member 408, the electrical insulating tube, and / or the ultrasonic transducer 214. Thus, when delivering the catheter 102 to the anatomical region to be treated, the backing member 408, the insulating tube, and / or the ultrasonic transducer 214 may be drawn into the hole 418 of the catheter 102, for example by pulling in an electrical cable, thereby providing the catheter 102 with sufficient rigidity and enabling safe delivery of the catheter 102.

[0079] Referring to Figure 5, a side view of a tissue treatment system with a compliant balloon inflated to a first expansion diameter according to one embodiment is shown. In certain embodiments, the balloon 108 is compliant (flexible) and configured to deploy within a wide range of lumen, blood vessel, or artery sizes. For example, the balloon 108 may be adaptable to arteries having an inner diameter in the range of 3 mm to 8 mm. Thus, using the compliance balloon 108 has the advantage of allowing only one catheter 102 to be used during the procedure, and in the case of renal nerve removal, for example, the surgical time can be reduced from, for example, about 1 hour to about 15 minutes. In certain embodiments, the use of a compliant balloon has the advantage of reducing the complexity of the procedure (surgery) and thereby reducing the incidence of complications.

[0080] In certain embodiments, the tissue treatment system 100 is configured to measure the size of a lumen, blood vessel, or artery. Since the balloon 108 is configured to accommodate a wide range of body cavity sizes, such as a renal artery or accessory artery ranging from approximately 3 mm to 9 mm, the controller 104 may be programmed to automatically inflate the balloon 108 to the appropriate diameter. Such automation advantageously improves the complexity of the procedure and reduces the risk of user error. In certain embodiments, the tissue treatment system 100 with the compliant balloon 108 does not require the user to select a balloon size and / or change catheters to provide multiple balloon sizes during a single procedure (surgery).

[0081] The compliant medical balloon 108 may include a balloon wall 502, which may have a generally annular cross-section at any longitudinal position. More specifically, the balloon wall 502 may have an outer surface that expands to contact the target tissue and an inner surface that defines the interior 504 of the balloon 108. As previously stated, the transducer 214 may be attached directly or indirectly (e.g., via an electrical cable) to the catheter shaft 212.

[0082] The transducer 214 may be positioned inside 504 of the balloon 108. More specifically, the balloon 108 may have a balloon body 506 that radially surrounds the transducer 214. For example, the balloon body 506 may be a substantially cylindrical portion of a balloon wall 502 that extends radially around the transducer 214 with respect to the longitudinal axis of the catheter shaft 212. The balloon body 506 may extend longitudinally between a plurality of corners 508. For example, a distal corner 508A may define the distal range of the balloon body 506, and a proximal corner 508B may define the proximal range of the balloon body 506. In one embodiment, the distance between the corners 508 defining the length of the balloon body 506 may be greater than or equal to the length of the transducer 214. More specifically, the length of the balloon body may be at least the length of the transducer 214. Therefore, the transducer 214 can be positioned such that its proximal end is distal to the proximal corner 508B of the balloon 108, and its distal end is proximal to the distal corner 508A of the balloon 108. The corners 508 can transition (transition) the balloon body 506 into multiple shoulder portions 510. Furthermore, in addition to the transition (transition) of sections of the balloon 108, the shape of the corners 508 can primarily affect the balloon 108's ability to center the transducer 214 within the target vessel 302.

[0083] In one embodiment, the multiple shoulder portions 510 include a distal shoulder portion 510A (the distal side of the balloon body 506) that connects the balloon body 506 to the distal attachment section 512A of the balloon wall 502. Similarly, a proximal shoulder portion 510B (the proximal side of the balloon body 506) may connect the balloon body 506 to the proximal attachment section 514B of the balloon wall 502. Thus, the multiple shoulder portions 510 transition (transition) the portion of the balloon wall 502 that connects the balloon 108 to the catheter shaft 212 to the portion of the balloon wall 502 that interacts with the target tissue during expansion.

[0084] The transducer 214 may be attached to an insulating tube and / or a backing member 408. In this case, the proximal attachment section 514B may be attached to the catheter shaft 212 proximal to the transducer, while the distal attachment section 514A may be attached to the transducer, the backing member 408, or the support tip 308. The attachment section may be connected to the catheter shaft 212 via a thermal joint, adhesive joint, or mechanical joint that airtightly seals the balloon 108 to the catheter shaft 212. Thus, the interior 504 of the balloon 108 between the attachment sections may surround the transducer 214, providing space for the expansion / cooling fluid to circulate around the transducer 214 not only during treatment but also before and / or after treatment.

[0085] In contrast to a compliant balloon 108 that primarily functions to occlude a target anatomical structure, it will be understood that the balloon 108 of the tissue treatment system 100 functions to center the transducer 214 within the target vessel 302. However, the flexibility of the balloon 108 required to achieve the inflation method described below may cause the transducer 214 to be eccentric with respect to the vascular lumen if certain features are not implemented in the balloon 108. More specifically, the shape and material of the balloon 108 may be provided to realize a compliant balloon 108 that has sufficient support to center the transducer 214 within the target vessel 302 during use, as described below.

[0086] The shape of the balloon 108 can contribute to optimally centering the transducer 214 within the target vessel 302. In one embodiment, the balloon body 506 and a number of shoulders 510 are joined at a rounded corner 508. The corner 508 can be considered "rounded" because the transition between the shoulders 510 and the balloon body 506 is not acute or angular, but rather has a smooth, arc-shaped profile. Such a profile can be described as having a complete radius, in contrast to the segmentable (discontinuous) radial changes seen in medical balloons typically used in angioplasty, for example. Compared to balloon shapes with acute corners, the rounded corners 508 of the balloon 108 function to maintain the catheter shaft 212 (and the transducer 214 attached to the catheter shaft 212) in a centered state within the target vessel 302 when the balloon 108 is inflated within the target vessel 302.

[0087] The material of the balloon 108 can contribute to optimally centering the transducer 214 within the target vessel 302. For example, in a particular embodiment suitable for renal nerve removal, the balloon 108 may be composed of nylon, polyether block amide (PEBAX®), or other suitable polymers. In one embodiment, the balloon wall 502 is formed from an elastomer material. For example, the elastomer material may include a urethane material such as thermoplastic polyurethane (TPU). The TPU may be a polyether-based TPU such as Pellethane®. Alternatively, the balloon wall 502 may be formed from another medical-grade polyether-based TPU such as Isothane®.

[0088] Isothane® is a urethane material with strictly controlled material specifications. Compared to other types of urethane, Isothane® may be particularly useful in that it exhibits less variation in material properties between material lots. More specifically, lot by lot, Isothane® has less gel and more consistent blockchain compared to other materials. Therefore, in one embodiment, the raw material used to form balloon 108 is Isothane®.

[0089] The hardness of the balloon material can contribute to the compliance (flexibility) of the balloon 108, for example, its ability to expand to fit the diameter of various vascular lumens. This hardness can also contribute to the balloon 108's ability to center and support the transducer 214. Therefore, the material used to form the balloon wall 502 may have a Shore durometer hardness between approximately 95A and 55D. More specifically, the balloon wall material may have a Shore D durometer hardness in the range of 50 to 60. For example, the balloon 108 may be formed from Pellethane® having a Shore D durometer hardness of 55, or from Isothane® having a Shore durometer hardness of 5095A, 7195A, or 5055D. In certain embodiments, it has been shown that a balloon wall 502 formed from Isothane® having a Shore D durometer hardness of 55 can yield excellent results in balancing performance targets between flexible expandability and support strength.

[0090] The inflation of a non-compliant balloon is limited by the balloon itself; that is, even when inflated at various pressures within the expected operating range, the balloon's diameter is generally fixed. Therefore, the balloon's diameter can only accommodate a limited range of vascular sizes. On the other hand, a compliant balloon can employ multiple inflation methods, allowing it to accommodate a wider range of vascular sizes. The compliant medical balloon 108 of the tissue treatment system 100 described above can be deployed into the target vessel 302 using one of several inflation methods. Such inflation methods may be called the "pressure-limited approach," the "arterial-limited approach," and the "hybrid approach."

[0091] The pressure-limiting approach involves juxtaposing the balloon with various vessel sizes by using specific inflation pressures to achieve specific balloon diameters. The arterial-limiting approach involves using a constant inflation pressure, which is used regardless of the arterial diameter. The hybrid approach is a combination of the arterial-limiting and pressure-limiting approaches. The hybrid approach involves using a constant inflation pressure to juxtapose smaller arterial diameters and using different (higher) inflation pressures to juxtapose larger arterial diameters. At low pressures, arterial strength effectively determines the size of balloon 108. On the other hand, at higher pressures, balloon pressure determines the size of balloon 108. These inflation paradigms are described in more detail below.

[0092] Referring further to Figure 5, the balloon is illustrated in a first state (more specifically, in the state of first expansion diameter). The expansion diameter may be the external dimension of the balloon body 506. In one embodiment, the balloon wall 502 has a shape and rigidity such that when the compliant balloon 108 is expanded to a first expansion pressure of 10 psi, the balloon body 506 of the balloon wall 502 has a cylindrical profile and a first expansion diameter of 3.5 mm to 6 mm (as described herein). The expansion pressure may correspond to the flow rate of the fluid circulating inside the balloon 108 between the inlet channel 403 and the outlet channel 405. For example, the fluid may be circulated at a flow rate of 15 to 35 mL / min (e.g., 25 to 35 mL / min) to expand the balloon 108 to an expansion pressure of 10 psi, resulting in a first expansion diameter of 3 to 6 mm (e.g., 3.5 to 6 mm). The balloon body 506 of balloon 108 may have a first expansion diameter of 3.5 mm at a first expansion pressure of 10 psi and a flow rate of 30 mL / min. The term "(flowrate)" can also be expressed as two words, namely "flow" and "rate".

[0093] In certain embodiments used in the pressure-limiting approach, a single balloon 108 may have an expansion diameter that directly correlates with the pressure inside the balloon 108. More specifically, the outer diameter of the balloon 108 directly correlates with the pressure inside the balloon 108. According to such embodiments, the higher the pressure, the larger the balloon 108 becomes. The balloon 108 may have an expansion range (expansion diameter) of 3.5 to 9 mm. More specifically, when the balloon 108 is expanded to the state shown in Figure 5, it may have a nominal size of 3.5 mm, but as the expansion pressure increases, the expansion diameter may also increase.

[0094] Referring to Figure 6, a side view is shown of a tissue treatment system comprising a compliant balloon inflated to a second inflation diameter according to one embodiment. When the medical balloon 108 is inflated to a second inflation diameter, e.g., 8 mm, the balloon wall 502 may have essentially the same sections as described above. More specifically, the medical balloon 108 may include a plurality of attachment sections 512, a plurality of shoulders 510, and a balloon body 506. The plurality of corners 508 transitioning the balloon body 506 to the plurality of shoulders 510 may be in a rounded form. In one embodiment, the plurality of arched corners 508 may have the same (common) radius as the balloon body 506 and the plurality of shoulders 510, and the balloon wall 502 may have a single arched profile having the same (common) radius between the distal attachment section 512 and the proximal attachment section 514. As shown in Figure 5, the balloon body 506 may be longer than the transducer 214 attached to the catheter shaft 212 and may surround the transducer 214. As shown in the figure, multiple shoulder portions 510 may be rounded, but the balloon 108 may instead have angular shoulder portions.

[0095] In one embodiment, the balloon wall 502 has a shape and rigidity such that when the compliant balloon 108 is inflated to a second inflation pressure of 30 psi, the balloon body 506 of the balloon wall 502 has a cylindrical profile and a second inflation diameter of 8 mm to 9 mm (as described herein). The inflation pressure can correspond to the flow rate of the fluid circulating inside 504 of the balloon 108 between the inlet channel 403 and the outlet channel 405. For example, the fluid may be circulated at a flow rate of 35 to 50 mL / min (e.g., 40 to 45 mL / min) to inflate the balloon 108 to an inflation pressure of 30 psi, resulting in a second inflation diameter of 8 to 9 mm. For example, the balloon body 506 of the balloon 108 may have a second inflation diameter of 8 mm at a flow rate of 40 to 45 mL / min with a second inflation pressure of 30 psi.

[0096] Referring to Figure 7, a graph of the balloon pressure curve of a balloon inflated according to a pressure-limiting approach according to one embodiment is shown. In this pressure-limiting approach, balloon 108 may have a pressure curve close to an ideal inflation curve 702. The ideal inflation curve 702 may extend linearly from a first inflation diameter of 3.5 mm at a first inflation pressure of 10 psi to a second inflation diameter of 8 mm at a second inflation pressure of 30 psi. Thus, balloon 108 can correspond to the vascular lumen diameter of 3.5 to 8 mm in the same or multiple vessels. More specifically, the inflation diameter 704 of balloon 108 corresponds to the inflation pressure 706 of balloon 108.

[0097] The balloon 108 can be inflated by circulating an expansion fluid 306 within it. More specifically, circulating the expansion fluid 306 within the balloon 108 generates an expansion pressure that expands the balloon 108 to its expansion diameter. The expansion pressure can be proportional to the flow rate. Thus, the expansion fluid 306 can be circulated within the balloon 108 based on the lumen diameter 320 of the target vessel 302 to inflate the balloon 108 to a desired size. For example, the flow rate associated with a second expansion pressure (and second expansion diameter) may be greater than the flow rate associated with a first expansion pressure (and first expansion diameter). As an example, the expansion fluid 306 may be circulated within the balloon 108 at a flow rate of 25-45 mL / min to achieve an expansion diameter 704 along an ideal expansion curve 702. In one embodiment, if the expansion fluid 306 is sterile water, the flow rate may be 30 mL / min to achieve an expansion pressure of 10 psi associated with an expansion diameter of 3.5 mm. If the expansion fluid 306 is sterile water, the flow rate may be 40–45 mL / min to achieve an expansion pressure of 30 psi associated with an expansion diameter of 8 mm. In another embodiment, if the expansion fluid 306 is D5W, the flow rate may be 27 mL / min to achieve an expansion pressure of 10 psi associated with an expansion diameter of 3.5 mm. If the expansion fluid 306 is D5W, the flow rate may be 40 mL / min to achieve an expansion pressure of 30 psi associated with an expansion diameter of 8 mm. Thus, the pressure limiting approach can achieve an expansion pressure of 10–30 psi by utilizing a flow rate of at least 30 mL / min. Flow rates of 30 mL / min or higher have been shown to circulate the fluid sufficiently to adequately cool the tissue during renal nerve debridement.

[0098] In one embodiment, the balloon 108 approximates an ideal inflation curve 702 over several inflation cycles. For example, when the tissue treatment system 100 is introduced into the renal artery, the balloon 108 may be inflated to a first inflation diameter (or second inflation diameter) in the first inflation cycle (708). The balloon 108 may be inflated one or more additional times, for example, up to a fifth inflation cycle (710), to treat different areas along the length of the renal artery. Using the aforementioned materials, the inflation curves of the balloon 108 in each inflation cycle approximate each other and approximate an ideal pressure curve. For example, when the balloon 108 is formed from Isothane® 55D, the inflation diameter when the balloon 108 is inflated for the first time (708) is within 10% of the inflation diameter when the balloon 108 is inflated for the fifth time (710). In contrast, balloons formed from other materials not considered above may exhibit inconsistent inflation curves over multiple cycles. For example, a balloon formed from other materials not considered above may show that the Nth (712) inflation diameter differs from the first (708) inflation diameter by more than 10%. Therefore, the balloon 108 described herein provides good inflation consistency, allowing a single device to be inflated multiple times to treat the same or different blood vessels during a single procedure (surgery).

[0099] Referring to Figure 8A, a side view of balloon 108 with wrinkles 800 is shown when balloon 108 is inflated to a size smaller than its nominal inflated diameter. These wrinkles can occur while the balloon is inserted into a target body cavity having a lumen diameter smaller than its nominal inflated diameter. For example, balloon 108 may have a nominal inflated diameter of 8 mm (or 5 mm or 6 mm, etc.) but may be inserted into a portion (also called a segment) of a body cavity (e.g., a renal artery) having a lumen diameter of 3.5 mm. Therefore, when balloon 108 is placed in a target body cavity having a lumen diameter smaller than its nominal inflated diameter (also called the nominal balloon diameter), the balloon body contacts the body cavity wall before balloon 108 reaches its nominal inflated diameter (also called the nominal balloon diameter). Thus, the combination of arterial hoop strength and low inflation pressure can keep balloon 108 at an inflated diameter smaller than its nominal inflated diameter and maintain the balloon body in a substantially cylindrical profile. For example, the hoop strength and inflation pressure of the renal artery may prevent the compliant balloon 108 from expanding to its nominal inflation diameter (also called the nominal balloon diameter). In smaller vessels, the balloon 108 needs to accommodate a wider range of cavity dimensions, some of which may exceed the nominal balloon diameter, and therefore needs to be made of extra or thicker material (folded) compared to a balloon 108 intended to accommodate only small cavities. Consequently, wrinkles 800 may occur that could be eliminated upon expansion in a larger cavity. More specifically, when the balloon 108 is inflated in a target vessel (also called a cavity) using an arterial restriction approach, the target vessel may constrain the balloon 108, resulting in the balloon 108 having several wrinkles 800 in the vessel wall, where extra material is folded to accommodate a diameter smaller than the nominal inflation diameter. The compliant balloon 108 may be a Pellethane® balloon having a Shore D durometer hardness of 55, having a double-wall thickness of 0.0004 to 0.0014 inches (e.g., 0.0009 inches), and may contain a plurality of wrinkles 800.

[0100] Referring to Figure 8B, a perspective view of a balloon having a spiral fold according to one embodiment is shown. The balloon 108 may have a proximal balloon end 802 and a distal balloon end 803. The balloon ends 802, 803 may be the ends of the cylindrical portion of the balloon 108, and are generally also called legs, neck, or tail. The balloon 108 may be a compliant or non-compliant balloon and may have balloon tapered sections 814, 816 (generally called balloon shoulders) extending from the balloon legs 802, 803 to a central operating section 818. The balloon shoulders 814, 816 may be (truncated) conical or barrel-shaped, or may have other shapes in which the diameter increases between each balloon leg 802, 803 and the operating section 818. The operating section 818 may also be called the balloon body 818.

[0101] Figure 8B shows the working section 818 between the balloon shoulders 814 and 816 in a partially inflated state. In this partially inflated (or deflated) state, the balloon 108 has a plurality of helical folds 808 extending around the longitudinal axis 806. More specifically, when the balloon 108 is not fully inflated, for example, when the balloon has an inflation diameter less than the nominal inflation diameter, the helical folds 808 may be present on the balloon wall. The helical folds 808 may extend between the proximal balloon end 802 and the distal balloon end 803. More specifically, each helical fold 808 may have a proximal fold end 810 and a distal fold end 812, and the fold may extend helically between these fold ends while rotating around the longitudinal axis 806.

[0102] Referring to Figure 8C, a perspective view of a balloon having longitudinal folds according to one embodiment is shown. Optionally, the balloon 108 is folded to form a plurality of longitudinal folds 822. More specifically, each fold may have a fold edge 824 extending mainly longitudinally and parallel to the longitudinal axis 806 from a proximal fold end 820 to a distal fold end 826. The folds of the balloon may be formed by a wrapping or pleating operation. In a partially inflated (or deflated) state, the balloon 108 includes a plurality of longitudinal folds 822 extending around the longitudinal axis 806. More specifically, when the balloon 108 is not fully inflated, for example, when the balloon has an inflation diameter less than the nominal inflation diameter, longitudinal folds 822 may be present on the balloon wall.

[0103] Referring to Figure 8D, a cross-sectional view of a balloon 108 having a longitudinal fold introduced in Figure 8C, according to one embodiment, is shown. The fold edge 824 may be the vertex region of the fold where the outward surface of the balloon fold meets the inward surface of the balloon 108. More specifically, the fold edge 824 may be the visual edge on which the balloon material folds over itself. The fold edge 824 does not necessarily have to be a perfect straight line, but should suggest a straight longitudinal line. The balloon 108 may have multiple folds, each fold may have a fold edge 824. Furthermore, the fold edges 824 may be separated from each other by a clocking angle 832. The clocking angle 832 is the angle between a first radial line extending from the longitudinal axis 806 through the first fold edge 824 and a second radial line extending from the longitudinal axis 806 through the second fold edge 824. The clocking angle 832 may be relatively constant along the length of the balloon 108 between longitudinal folds 822 and / or between helical folds 808, as described later. For example, the clocking angle 832 may be about 120 degrees in the illustrated cross section, and may also be about 120 degrees between the same two folds in other cross sections along the length of the balloon 108. Multiple folds of the balloon 108 may include two or more folds. For example, as shown in Figure 8D, multiple folds may include three folds. Alternatively, folds (either longitudinal or helical) may include two folds, four folds, etc. Multiple folds may be evenly distributed such that the clocking angle 832 of each pair of folds is the same. For example, if there are four folds, the clock angle 832 may be 90 degrees; if there are three folds, the clock angle 832 may be 120 degrees; if there are two folds, the clock angle 832 may be 180 degrees, and so on. Alternatively, the folds may be unevenly distributed, and the clocking angle 832 may vary between different pairs of fold edges 804. For example, balloon 108 may have three folds, comprising a first pair of fold edges 804 separated by 180 degrees, a second pair of fold edges 804 separated by 90 degrees, and a third pair of fold edges 804 separated by 90 degrees. Embodiments having three folds are described herein. However, such examples are not limiting.It will be understood that balloon 108 may have any number of folds.

[0104] Referring to Figure 8E, a perspective view of a balloon having a helical fold according to one embodiment is shown. In one embodiment, a plurality of longitudinal folds 822 can be converted into a plurality of helical folds 808. Alternatively, a plurality of helical folds 808 can be directly introduced into the balloon 108 without performing an intermediate operation to form a plurality of longitudinal folds 822. In either case, the distal balloon end 803 can be rotated relative to the proximal balloon end 502 to form a plurality of helical folds 808 in the balloon 108. Therefore, the process of forming a plurality of helical folds 808 includes the step of twisting the balloon 108 to create a plurality of folds, or the step of folding the balloon and then twisting the balloon to convert the folds from longitudinal folds 822 to helical folds 808. The step of twisting the balloon 108 can pre-set the balloon material and reduce the balloon profile. In one embodiment, the balloon 108 is twisted at a twist angle such that the fold edges 804 of the folds extend spirally from the proximal fold edge 810 to the distal fold edge 812. Thus, the folds position multiple fold edges 804 at predetermined locations around the balloon 108. When the balloon 108 is inflated and deflated, the folds remain at these locations, resulting in a repeatable distribution of excess balloon material to the transducer 214. In a partially inflated (or deflated) state, the balloon 108 has multiple spiral folds 808 extending around the longitudinal axis 806. More specifically, when the balloon 108 is not fully inflated, for example, when the balloon has an inflation diameter less than the nominal inflation diameter, spiral folds 808 may be present on the balloon wall.

[0105] Referring to Figure 8F, a cross-sectional view of a balloon having a helical fold according to one embodiment is shown. The helical fold 808 may have a twist angle 852. The twist angle 852 may be defined by the angular displacement between the proximal fold end 810 and the distal fold end 812. The twist angle 852 may be 90 degrees, 120 degrees, 180 degrees, or any other arbitrary angle. The twist angle 852 may correspond to the clocking angle 832. The illustrated cross-section may be taken at the distal fold end 812 so as to traverse the longitudinal axis 806, and the proximal fold end 810 may be hidden behind an adjacent fold in Figure 8F. In the illustrated example, the angular displacement may be 180 degrees, and the resulting clocking angle 832 may be 120 degrees. Thus, the twist angle 852 may be greater than the clocking angle 832. In one embodiment, for example, when a selective operation to form a longitudinal fold 822 is omitted, the twist angle 852 introduces a clocking angle 832. More specifically, the twisting step of the balloon 108 can cause the balloon material to fold on itself, forming a helical balloon fold. In some cases, the twist angle 852 required to achieve a desired clocking angle 832 may correspond to that clocking angle 832. More specifically, a twist angle 852 of 120 degrees may produce a fold having a clocking angle 832 of 120 degrees. Alternatively, the flexibility of the balloon material may require the use of a larger twist angle 852 to achieve the desired clocking angle 832. For example, a twist angle 852 of 180 degrees may be used to produce a clocking angle 832 of 120 degrees. Thus, the twist angle 852 may be equal to or greater than the clocking angle 832. For example, the torsional angle 852 can be within an angular displacement range from an angle equal to the clocking angle 832 to an angle equal to five times the clocking angle 832. For example, when the clocking angle 832 is 120 degrees, the torsional angle 852 can be between 120 and 600 degrees.

[0106] The foregoing description is illustrative and not limiting. More specifically, the balloon 108 may not require a specific clocking angle 832 or twist angle 852 to provide a useful function in accordance with the principles described herein. The twist angle 852 can be any angle that distributes (disperses) the excess material of the balloon 108 into the helical fold 808, thereby biasing the balloon 108 to the same contraction profile or form when the balloon is inflated and deflated. Thus, the twist angle 852 may introduce repeatable helical folds 508 into the balloon wall. However, the helical fold 808 may have a clocking angle 832 independent of the twist angle 852.

[0107] In certain embodiments, balloon 108 is a compliant balloon. As described above, balloon 108 may include an elastomer material. The elastomer material may include, for example, a urethane material with a low durometer hardness (e.g., Shore hardness 80A-55D), as described above. Furthermore, the material of balloon 108 may be thin. For example, the double-wall thickness of balloon 108 may be 0.0005 inches to 0.0015 inches. Thus, balloon 108 can be very flexible and a torsional bias may introduce pleats when the thin elastomer material folds over itself.

[0108] When balloon 108 is rotated to introduce a torsional bias into the balloon material, the distal balloon end 803 may be connected to (e.g., attached to, mounted on, etc.) the distal tip and / or insulating tube of the catheter shaft 212. Balloon 108 may be sealed to the catheter shaft 212 such that the interior of balloon 108 accommodates an ultrasonic transducer 214, and may be filled with a cooling fluid to inflate the balloon. The torsional bias of balloon 108 within the assembled tissue treatment catheter 102 may be beneficial in creating a predetermined fold within the balloon to facilitate predictable balloon deployment. This predetermined fold is positioned predictably and repeatably during inflation and deflation, reducing variations in ultrasound treatment as acoustic energy passes through the balloon wall. Furthermore, the fold may provide a thicker balloon wall around the transducer 214 when balloon 108 is deflated, thereby enhancing protection of the ultrasonic transducer.

[0109] As used herein, the term “crease” is intended to include wrinkles, such as the wrinkle 800 described above with reference to Figure 8A. Therefore, when the term “crease” is used herein, such a “crease” could be, for example, the wrinkle 800 described above with reference to Figure 8A, and / or the spiral crease 808 described above with reference to Figures 8B, 8E, and 8F, and / or the longitudinal crease 822 described above with reference to Figures 8C and 8D, but is not limited to these.

[0110] In certain embodiments, the balloon 108 may be designed such that folds (e.g., wrinkles) within the balloon do not significantly interfere with the energy delivery of the catheter. For example, the folds may have a predictable fold pattern that interferes with energy delivery only minimally. More specifically, the predictable fold pattern may have a low folding density and / or have folds (only) that occur in specific locations that are not present (do not overlap) with the main energy delivery pathway.

[0111] In other embodiments, the folds (e.g., 800, 808, and / or 822) may form a predictable fold pattern (e.g., a wrinkle pattern) that intentionally obstructs the delivery of acoustic energy, thereby attenuating the acoustic energy radiated from the transducer 214 within the balloon 108, so that when the balloon 108 is adjacent to the wall of a relatively small diameter cavity segment, less acoustic energy is delivered to the tissue being treated compared to when the balloon 108 is adjacent to the wall of a relatively large diameter cavity segment. Such embodiments utilize the balloon 108 to help deliver an appropriate amount of acoustic energy to the target tissue being treated. More specifically, a compliant balloon, such as balloon 108 shown in Figures 8A to 8F, may be designed such that folds develop in a predictable manner, thereby allowing the folded (wrinkled) balloon surface to generate additional acoustic reflections compared to when balloon 108 is inflated to a state without folds (or fewer and / or smaller folds) compared to when balloon 108 is inflated to a state without folds (e.g., wrinkles). In such embodiments, the folds allow sound waves to travel a longer propagation path before they exit balloon 108 and reach the target tissue being treated. This increase in the acoustic propagation path inside the balloon results in acoustic energy loss inside the balloon before the acoustic energy exits the balloon. Furthermore, the folds effectively increase the thickness of the balloon in the portion where the folds (e.g., wrinkles) are present. The thickness of the balloon material affects the amount of attenuation produced by the balloon (i.e., the thicker the balloon material, the greater the attenuation), and the effective increase in balloon thickness caused by folds also contributes to the attenuation of acoustic energy. These two factors result in a higher rate of acoustic energy loss before the acoustic energy is transmitted to the target tissue compared to using a balloon of the same size but without folds (e.g., wrinkles).

[0112] More generally, in certain embodiments, the compliant balloon 108 is designed to at least partially attenuate a portion of the acoustic energy radiated by the transducer 214 when the diameter of the cavity segment into which the balloon is inserted falls within a smaller diameter subset of a specified diameter range, compared to when the diameter of the cavity segment falls within a larger diameter subset of the specified diameter range, thereby reducing the amount of acoustic energy passing through the folded (e.g., wrinkled) balloon material. For example, when the diameter of the cavity segment is 3 mm, less acoustic energy passes through the folded (e.g., wrinkled) balloon material compared to when the diameter of the cavity segment is 8 mm. As another example, when the diameter of the cavity segment is 3 mm, less acoustic energy passes through the folded (e.g., wrinkled) balloon material compared to when the diameter of the cavity segment is 4.9 mm. As yet another example, when the diameter of the body cavity segment is 5 mm, less acoustic energy passes through the folded (e.g., wrinkled) balloon material compared to when the diameter of the body cavity segment is 8 mm.

[0113] The compliant balloon 108 described herein may be inflated using an arterial restriction approach, a pressure restriction approach, or a hybrid thereof. In the arterial restriction approach, the balloon 108 is inflated to a predetermined inflation pressure regardless of the vascular lumen diameter. More specifically, the low pressure used in the arterial restriction approach may be a fixed pressure used regardless of the vascular lumen diameter. For example, the predetermined inflation pressure may be 10 psi or less and may be used in any target vessel 302 having a vascular lumen diameter smaller than the nominal inflation diameter of the balloon 108. It will be understood that this inflation paradigm differs from a pressure restriction approach that utilizes an inflation pressure based on the target lumen diameter.

[0114] Referring to Figure 9, a graph of the balloon pressure curve of a compliant balloon 108 inflated according to a hybrid inflation approach according to one embodiment is illustrated. In the hybrid inflation approach, a single compliance balloon 108 having a nominal inflation diameter may be used to treat both vascular lumen diameters smaller than the nominal inflation diameter and vascular lumen diameters larger than the nominal inflation diameter. The compliant balloon 108 can similarly treat lumen diameters in different vessels, or lumen diameters in different parts of the same vessel (e.g., the distal and proximal parts of the vessel). The balloon 108 may be sized to be a size midpoint or near a midpoint suitable for a range of body lumen diameters. For example, for a typical renal artery lumen size, a balloon 108 with a nominal inflation diameter of 6.75 mm may be provided.

[0115] The hybrid approach is a combination of an arterial restriction approach and a pressure restriction approach. In the aforementioned example of balloon 108 having a nominal inflated diameter of 6.75 mm, balloon 108 can be inflated to a low pressure (e.g., 10 psi) for arteries smaller than 6.75 mm. Over this inflated range, balloon 108 is within the operating range 902 of the arterial restriction approach. Within the operating range 902 of the arterial restriction approach, balloon 108 is arterially restricted. Therefore, when the compliant balloon 108 is inflated to a first inflated pressure in a renal artery (or portion of a renal artery) having a first arterial diameter smaller than the nominal inflated diameter of the compliant balloon 108, the hoop strength of the renal artery and the inflated pressure (as a result of their interaction) prevent the compliant balloon 108 from expanding to its nominal inflated diameter.

[0116] In contrast, for arteries (or arterial portions) larger than the nominal inflated diameter (e.g., 6.75 mm), the pressure inside balloon 108 may be increased to increase the size of balloon 108. When balloon 108 operates beyond the nominal inflated diameter of 6.75 mm, it may operate within the operating range 904 of the pressure-limiting approach. Within the operating range 904 of the pressure-limiting approach, balloon 108 is pressure-limiting. Thus, when the compliant balloon 108 is inflated to a second inflated pressure higher than the first inflated pressure in a renal artery (or renal artery portion) having a second arterial diameter larger than the nominal inflated diameter of the compliant balloon 108, the second inflated pressure expands the diameter of the compliant balloon 108 to a size greater than its nominal inflated diameter. The inflated pressure may be gradually increased to gradually expand balloon 108 to be adjacent to (tightly attached to) the larger arterial diameter. The nominal inflation diameter of 6.75 mm is provided only as an example, and in the embodiments described above, the balloon 108 may have a nominal inflation diameter of 3.5 mm, 3.7 mm, 4.5 mm, 5.5 mm, 6.5 mm, or any other diameter that separates the operating range of the balloon 108 from the operating range of the balloon 108's pressure-limiting approach to the operating range of the balloon 108's arterial-limiting approach.

[0117] In one embodiment, the compliant balloon 108 has a nominal expansion diameter of approximately 4 mm. When the compliant balloon 108 is inflated to a first expansion pressure within the first arterial diameter of the renal artery, which has a diameter of less than 4 mm, the hoop strength of the renal artery and the expansion pressure (as a result of their interaction) prevent the compliant balloon 108 from expanding to a diameter larger than the first arterial diameter of the renal artery. On the other hand, when the compliant balloon 108 is inflated to a second expansion pressure higher than the first expansion pressure within the renal artery, which has a second diameter greater than 4 mm, the diameter of the compliant balloon 108 expands due to the second expansion pressure so that it is adjacent to (juxtaposed with) the second diameter of the renal artery.

[0118] As a further example of a hybrid approach, compliant balloon 108 may be a Pellethane® balloon with a Shore D durometer hardness of 55 and a nominal inflated diameter of 5.5 mm. Compliant balloon 108 can be inflated at a constant low balloon pressure to be adjacent to smaller arterial diameters, but as the arterial diameter gradually increases, the pressure can be increased to match the balloon size to the arterial diameter. Table 1 shows the balloon pressures used to reach the balloon diameter size range. Note that the inflation pressure for diameters up to the nominal inflated diameter of the compliant balloon, and for diameters slightly larger than the nominal inflated diameter, is a single low pressure of 10 psi. The inflation pressure is then gradually increased to achieve an inflated diameter of 704 exceeding 6 mm. Table 1. Balloon inflation data TIFF2026516145000002.tif34155

[0119] As previously mentioned, the inflation pressure depends on the flow rate of the inflation fluid 306 within balloon 108. Table 2 shows the approximate flow rates for three pressures selected from the full range of 10–20 psi that can be used to inflate balloon 108 using the hybrid approach. Note that these flow rates are near or above approximately 30 mL / min. These flow rates have been demonstrated to effectively cool the tissue during renal nerve decongestion. Table 2. Balloon flow rate data TIFF2026516145000003.tif34155

[0120] Exemplary details of the cartridge 112 and reservoir 110 described in the explanatory section of Figure 1 are described below with reference to Figure 10. The cartridge 112 and / or reservoir 110 may be part of a fluid supply subsystem. However, it should be noted that within the scope of embodiments of the art described herein, alternative fluid supply subsystems may be used to supply and circulate the cooling fluid to the balloon 108. Referring to Figure 10, the reservoir 110 is shown as one that may be implemented as a fluid bag. The fluid bag may be identical or similar to an intravenous (IV) bag in that it may be suspended from a hook or the like. The reservoir 110 and cartridge 112 may be disposable and replaceable articles.

[0121] The reservoir 110 is fluidically coupled to the cartridge 112 via a pair of fluid paths. One of these is used as a fluid outlet path (supplying fluid from the reservoir to the cartridge), and the other is used as a fluid inlet path (returning fluid from the cartridge to the reservoir). The cartridge 112 is illustrated to include a syringe pump 1040, which includes a pressure syringe 1042a and a vacuum syringe 1042b. The pressure syringe 1042a includes a barrel 1044a, a plunger 1046a, and a hub 1048a. Similarly, the vacuum syringe 1042b includes a barrel 1044b, a plunger 1046b, and a hub 1048b. The respective hubs 1048a and 1048b of syringes 1042a and 1042b are coupled to their respective fluid tubes or hoses. Cartridge 112 is also shown to include pinch valves VI, V2, V3, pressure sensors P1, P2, P3, and check valve CV. Although not specifically shown in Figure 10, the syringe pump 1040 may include one or more gears and stepping motors controlled by controller 104 (see Figure 1) to selectively operate the plungers 1046 of pressure syringe 1042a and vacuum syringe 1042b. Alternatively, the gears and / or stepping motors may be mounted within controller 104 and used to control the syringe pump 1040.

[0122] To at least partially fill the barrel of the pressure syringe 1042a with some of the cooling fluid stored in the reservoir 110, pinch valves V1 and V2 are closed, pinch valve V3 is opened, and the plunger 1046a of the pressure syringe 1042a is pulled, drawing the cooling fluid 1013 into the barrel 1044a of the pressure syringe 1042a. Next, pinch valve V3 is closed, pinch valves V1 and V2 are opened, and the plunger 1046a of the pressure syringe 1042a is pushed, causing the cooling fluid to be discharged from the barrel 1044a of the pressure syringe 1042a through the fluid tube attached to the hub 1048a of the pressure syringe 1042a. The cooling fluid discharged from the pressure syringe 1042a enters the fluid lumen 1070 (inside the catheter shaft 212) via the fluid inlet port 208 of the catheter 102, then enters the balloon 108, and at least partially fills the balloon 108. Simultaneously, by pulling the plunger 1046b of the vacuum syringe 1042b, the cooling fluid can be drawn out of the balloon into the fluid lumen 1072 (inside the catheter shaft), through the fluid outlet port 210 of the catheter 102, and then through the fluid tube attached to the hub 1048b of the vacuum syringe 1042b into the barrel 1044b of the vacuum syringe 1042b. In this way, the cooling fluid can be circulated through the balloon 108. The balloon 108 can be inflated by supplying it with more cooling fluid than is removed from it. One or more of the pressure sensors P1, P2, and P3 may be used to monitor the pressure inside the balloon 108 in order to achieve a target balloon pressure (e.g., 10 pounds per square inch (psi)). Once the balloon is inflated to the target pressure (e.g., 10 psi to 30 psi) and / or target size, the cooling fluid can be circulated through the balloon without increasing or decreasing the amount of fluid inside the balloon, by ensuring that the amount of fluid removed from the balloon 108 is equal to the amount of fluid supplied to the balloon 108.Furthermore, once the target balloon pressure is reached, the ultrasonic transducer 214 may be excited to emit ultrasonic energy, thereby treating the tissue surrounding the portion of the body cavity (e.g., a portion of the renal artery) into which the balloon 108 and transducer 214 are inserted. When the ultrasonic transducer 214 is emitting ultrasonic energy, it can be said that the ultrasonic transducer 214 is performing sonication, i.e., sonication is occurring. During sonication, a cooling fluid should be circulated through the balloon by continuously pushing the plunger 1046a of the pressure syringe 1042a and by continuously pulling the plunger 1046b of the vacuum syringe 1042b.

[0123] After sonication is complete, the balloon 108 should be deflated so that the catheter 102 can be removed from the body cavity, and the cooling fluid should be returned from the barrel 1044b of the vacuum syringe 1042b to the reservoir 110. To return the cooling fluid from the barrel 1044b of the vacuum syringe 1042b to the reservoir 110, pinch valves V1, V2, and V3 are all closed and the plunger of the vacuum syringe 1042b is pushed so that the cooling fluid is discharged from the barrel of the vacuum syringe 1042b, passes through check valve CV, and returns into the reservoir 110.

[0124] Pressure sensors P1, P2, and P3 may be used to monitor fluid pressure at various points along various fluid paths within the cartridge 112. These pressure readings may be provided to the controller 04 as feedback used to control the syringe pump 1040 and / or as feedback used for other purposes, such as determining the fluid pressure in the balloon 108. Furthermore, flow sensors F1 and F2 may be used to monitor the flow rate of cooling fluid injected into the balloon 108 (also referred to as being pushed in, supplied, or supplied), and to monitor the flow rate of cooling fluid withdrawn from the balloon 108 (also referred to as being pulled out or removed), respectively. Pressure readings obtained from pressure sensors P1, P2, and P3 may be provided to the controller 104, which may monitor the balloon pressure. Furthermore, flow rate measurements obtained from flow sensors F1 and F2 may be provided to the controller 104, which can monitor the flow rate of the cooling fluid being pushed into and withdrawn from the balloon 108. Additionally, one or more (additional or alternative) pressure sensors and / or flow sensors may be placed at additional or alternative locations along the fluid path supplying the cooling fluid to and from the balloon 108.

[0125] Figure 11A is used to illustrate an exemplary implementation of the controller 104 introduced in Figure 1. Referring to Figure 11A, the controller 104 is illustrated to include one or more processors 1112, memory 1114, user interface 1116, and ultrasonic excitation source 1118, but may include additional and / or alternative components. Although not specifically shown, the processors 1112 may be located on a control board (more commonly on a printed circuit board (PCB)) together with additional circuitry of the controller 104. The processors 1112 can communicate with memory 1114, which may be a non-temporary computer-readable medium for storing commands (instructions). The processors 1112 can execute such commands (instructions) and cause the system 100 to perform the methods described herein. The user interface 1116 interacts with the processor 1112 to transmit electrical signals at a selected operating frequency to the ultrasonic transducer 214 via the wires of the connecting cable 106 and the wires of the cable 282 extending through the catheter shaft 212. These wires electrically connect the controller 104 to the transducer 214, so that the controller 104 can transmit electrical signals to and receive electrical signals from the transducer 214. The processor 1112 can control the ultrasonic excitation source 1118, control the amplitude and timing of the electrical signals, and control the power level and duration of the ultrasonic signals emitted by the transducer 214. More generally, the controller 104 can control one or more ultrasonic processing parameters used to perform the ultrasonic processing. In certain embodiments, the excitation source 1118 can detect the electrical signals generated by the transducer 214 and transmit such signals to the processor 1112 and / or control board circuits. Although the ultrasonic excitation source 1118 in Figure 11A is shown as part of the controller, the ultrasonic excitation source 1118 can also be located outside of the controller 104, while still being controlled by the controller 104 (more specifically by the processor 1112 of the controller 104).

[0126] The user interface 1116 may include a touchscreen and / or buttons, switches, etc., and may allow the operator (user) to input patient data, select treatment parameters, view records stored in a storage / retrieval unit (not shown), and / or communicate with the processor 1112 in other ways. The user interface 1116 may include a voice activation mechanism for inputting patient data, or may be able to communicate with additional equipment, such as controller 104 being controlled via a separate user interface, such as a wired or wireless remote controller. In some embodiments, the user interface 1116 is configured to receive operator-defined inputs, which may include, for example, the duration of energy delivery, one or more other timing features of the energy delivery pulse (e.g., frequency, duty cycle, etc.), power, body cavity length, operating mode, patient parameters such as height and weight, and / or verification of arterial diameter, or a combination thereof. Exemplary operating modes may include, but are not limited to, system startup and setup, catheter preparation, balloon inflation, balloon juxtaposition verification, pre-cooling, sonication, post-cooling, balloon deflation, and catheter removal. In certain embodiments, user interface 1116 provides a graphical user interface (GUI) that instructs the user on how to properly operate system 100. User interface 1116 may also be used to display treatment data for confirmation and / or download, allow software updates, etc.

[0127] The controller 104 can also control the cooling fluid supply subsystem 1130. The cooling fluid supply subsystem 1130 may include the cartridge 112 and reservoir 110 described above with reference to Figures 1 and 10, but may also include alternative types of fluid pumps, etc. The cooling fluid supply subsystem 1130 is fluidically coupled to one or more fluid lumens (e.g., 327 and 328) in the catheter shaft 212, and these fluid lumens are fluidically coupled to the balloon 108. The cooling fluid supply subsystem 1130 may be configured to circulate the cooling fluid through the catheter 102 to the transducer 214 in the balloon 108. The cooling fluid supply subsystem 1130 may include elements such as a reservoir 110 holding the cooling fluid 1013, a pump (e.g., syringes 1042a, 1042b), a cooling coil (not shown), etc., to supply the cooling fluid to the internal space of the balloon 108 at a controlled temperature (preferably below body temperature). The processor 1112 interacts with the cooling fluid supply subsystem 1130 to control the inflow and outflow of cooling fluid to the balloon 108. For example, the processor 1112 may control a motor control device coupled to a drive motor associated with a pump to control the operating speed of the pump (e.g., syringes 1042a, 1042b). Such a motor control device may be used, for example, when the pump is a positive displacement pump such as a peristaltic pump. Alternatively or additionally, the control circuit may include structures such as controllable valves connected within the fluid circuit to change the resistance of the circuit to the fluid flow (not shown). The processor 1112 may monitor pressure readings obtained by pressure sensors (e.g., P1, P2, P3) to monitor and control the cooling fluid flowing through the catheter 102 and balloon 108. The pressure sensors may also be used to determine whether there is a blockage and / or leak in the catheter 102. While the balloon 108 is inflated, the pressure sensor may be used to maintain a desired pressure within the balloon 108, for example, a pressure between 10 psi and 30 psi, but is not limited to this embodiment.As will be described in more detail below, the processor 1112 may use sensor readings from one or more pressure sensors and / or other sensors to determine when the balloon 108 is adjacent to a body cavity and to estimate the inner diameter of the body cavity, and to select an appropriate amount of ultrasonic energy to be delivered to treat the tissue surrounding the body cavity.

[0128] Figure 11B is used to illustrate exemplary details of an ultrasonic excitation source 1118 according to a particular embodiment of the present technology. When the ultrasonic excitation source 1118 is used to generate a signal used to drive the transducer 214 of the catheter 102, the ultrasonic excitation source 1118 may also be referred to as a signal generator 1118. As shown in Figure 11B, the ultrasonic excitation source 1118 (also known as signal generator 1118) is communicatively coupled to the processor 1112 of the controller 104. The ultrasonic excitation source 1118 (also known as signal generator 1118) is illustrated as including a pulse generator 1132, a power amplifier 1134, a bidirectional coupler 1136, an output transformer 1138, and an output filter 1140. The ultrasonic excitation source 1118 (also known as signal generator 1118) is also illustrated as including a digital-to-analog converter (DAC) 1142 and a power supply 1144, which are collectively used to control the gain of the power amplifier 1134. The pulse generator 1132 generates signal pulses under the control of at least one of the processors 1112. More specifically, at least one of the processors 1112, or its tissue treatment control module 1152, controls the timing and frequency of the pulses generated by the pulse generator 1132.

[0129] The pulses generated by the pulse generator 1132 are amplified by the power amplifier 1134 to produce amplified pulses supplied to the output transformer 1138. The output transformer 1138 boosts the voltage of the pulses output by the power amplifier 1134 and electrically isolates the circuits and other components downstream of the output transformer 1138 (e.g., transducer 214) from the circuits upstream of the output transformer 1138 (e.g., power amplifier 1134 and pulse generator 1132). For example, the output transformer 1138 can boost a pulse with a peak-to-peak amplitude of 24V to a pulse with a peak-to-peak amplitude of 60V or 70V. The output filter 1140 shapes the output signal supplied to transducer 214, for example, converting a square wave pulse to a sinusoidal wave pulse. The output filter 1140 can also remove noise introduced by the output transformer 1138.

[0130] The bidirectional coupler 1136 is located in the signal path between the power amplifier 1134 and the transducer 214 and provides a signal indicating the forward power supplied to the transducer 214 (e.g., a signal proportional to the forward power) and a signal indicating the reflected power from the transducer 214 (e.g., a signal proportional to the reflected power). Figure 11B illustrates the bidirectional coupler 1136 coupled between the power amplifier 1134 and the output transformer 1138. In another embodiment, the bidirectional coupler 1136 may be located downstream of the output transformer 1138 and therefore closer to the transducer 214. The signal indicating the forward power supplied to the transducer 214 and the signal indicating the reflected power from the transducer 214 are converted from analog to digital signals by analog-to-digital converters (ADCs) 1152 and ADC 1154 and used as feedback signals provided to at least one of the processors 1112 to control the tissue treatment delivered by the transducer 214. This type of feedback is used to precisely control the power supplied to transducer 214.

[0131] [Single power and two power configurations] In certain catheter-based tissue therapy systems utilizing ultrasonic transducers, users of such systems are required to determine an accurate estimate of the diameter of the body cavity into which the catheter containing the ultrasonic transducer is to be inserted, so that they can select and use one of several (e.g., six) different catheters having one of several (e.g., six) different balloons of the appropriate size, and so that they can select and radiate an appropriate amount of acoustic energy from several (e.g., six) different possible amounts (e.g., with respect to six different power settings). Thus, existing catheter-based systems require considerable shelf space to store devices of various sizes. Furthermore, the cost of storing devices of various sizes can be very high. Also, a diverse product portfolio introduces manufacturing complexity associated with the production of a wide range of different device models. Moreover, the need to accurately estimate the diameter of the body cavity increases the time and complexity of tissue therapy surgeries utilizing such catheter-based tissue therapy systems. Such catheter-based tissue therapy systems may be referred to herein as conventional catheter-based tissue therapy systems.

[0132] Certain embodiments of the Technology described herein simplify tissue therapy systems and methods (also known as surgery) by eliminating the need for the user to accurately estimate the diameter of the body cavity segment into which the catheter is inserted, and by eliminating the need for multiple catheters to be manufactured by a manufacturer and purchased and stored by a medical facility. More specifically, in certain embodiments, when the diameter of the body cavity segment (also referred to as a portion) (in which an ultrasonic transducer is placed) is within a specified diameter range of at least 4 mm or at least 5 mm, the ultrasonic transducer of the catheter emits approximately the same amount of acoustic energy. In other words, as long as the diameter of the body cavity segment (in which the ultrasonic transducer is placed) is within a specified expected diameter range (e.g., between approximately 3 mm and approximately 8 mm), the ultrasonic transducer of the catheter emits approximately the same amount of acoustic energy to treat the target tissue surrounding the body cavity in which the ultrasonic transducer of the catheter is placed. This greatly simplifies the design of a tissue therapy system including a catheter, an excitation source (also referred to as a signal generator), and a controller. Furthermore, this significantly simplifies tissue therapy surgery by simplifying the steps that need to be performed by the user of the tissue therapy system, because the user does not need to accurately estimate the diameter of the body cavity or select from multiple different catheters for use in the surgery. This also significantly reduces the number of catheters that manufacturers need to produce and medical facilities need to purchase and store. The embodiments outlined herein may be referred to as single-power embodiments.

[0133] In one embodiment, when the diameter of a segment (also referred to as a part) of the body cavity (with an ultrasonic transducer positioned inside) is within a specified diameter range of at least 4 mm or at least 5 mm, approximately the same amount of acoustic energy is emitted by the ultrasonic transducer of the catheter, while during this time the total ablation area and ablation depth are maintained to prevent damage to the vascular wall, particularly to the endothelium and interlayer of the vascular wall, while allowing sufficient damage to the arterial nerve and / or periarterial nerve to be treatable. A minimum ablation distance from the arterial lumen (e.g., about 0.5 mm to about 1.5 mm) is maintained to protect (preserve) the arterial wall, while a maximum ablation distance is maintained to protect (preserve) the safety of the periarterial organs. For example, a lesion depth of 5 mm to 7 mm (and further, for example, 5.5 mm to 6 mm) can be maintained over a specified diameter range of at least 4 mm, at least 5 mm, or at least 6 mm.

[0134] In other embodiments, instead of the ultrasonic transducer of the catheter always emitting approximately the same amount of acoustic energy, the ultrasonic transducer emits a first amount of acoustic energy when the diameter of the segment of the body cavity (in which the ultrasonic transducer is located) is within a lower sub-range of a specified diameter range (at least 1 mm, at least 1.5 mm, at least 2 mm, or at least 2.5 mm), and the ultrasonic transducer emits a second amount of acoustic energy (greater than the first amount of acoustic energy) when the diameter of the segment of the body cavity (in which the ultrasonic transducer is located) is within an upper sub-range of the specified diameter range (at least 2.5 mm, at least 3 mm, at least 3.5 mm, at least 4 mm, or at least 4.5 mm). Such embodiments may be referred to herein as two-power embodiments. While not as simple as the single-power embodiment, the two-power embodiment still significantly simplifies the design, manufacture, and use of the tissue treatment system, including the catheter, excitation source, and controller, compared to the conventional catheter-based tissue treatment systems described above (which required determining an accurate estimate of the diameter of the body cavity into which the catheter was to be inserted, selecting and using one of several (e.g., six) different catheters with an appropriate balloon of the appropriate size, and selecting and radiating an appropriate amount of acoustic energy from several (e.g., six) different possible amounts). Advantageously, the two-power embodiment provides a total ablation area and ablation depth that allows for the treatment of sufficient arterial and / or periarterial nerve damage while preventing damage to the vascular wall, particularly damage to the endothelium and interlayer of the vascular wall. A minimum ablation distance from the arterial lumen (e.g., approximately 0.5 mm to approximately 1.5 mm) is maintained to protect (preserve) the arterial wall, while a maximum ablation distance is maintained to protect (preserve) the safety of the periarterial organs. For example, a lesion depth of 5mm to 7mm (or even 5.5mm to 6mm) can be maintained across the entire diameter range treated by the two power embodiments.The advantage of the two-power embodiment over the one-power embodiment is that lower power is used in smaller diameter sub-ranges of body cavity diameter, and higher power is used in larger diameter sub-ranges of body cavity diameter. Therefore, the two-power embodiment can provide safer and more effective tissue treatment over a wider range of body cavity diameters than the one-power embodiment.

[0135] The (common) tissue therapy systems in single-power and two-power embodiments include a catheter, a controller (also called a control unit), and an excitation source (also called a signal generator). In the following description, it is assumed that a tissue therapy system 100 including a catheter 102, a controller 104, and an excitation source 1118 is used. Furthermore, it is assumed that the catheter includes a distal portion (e.g., a shaft 212) on which an ultrasonic transducer 214 is located, and that the catheter is configured to be insertable into a body cavity (e.g., a renal artery) having a specified diameter range of at least 4 mm or at least 5 mm (e.g., about 3.0 mm to about 8.0 mm). However, it should be noted that alternative catheters, controllers, excitation sources, and transducers may also be used. The excitation source 1118 is configured to selectively supply energy to the ultrasonic transducer 214 of the catheter 102, in which case the ultrasonic transducer 214 emits an acoustic signal having acoustic frequency, power, and duration. The controller 104 is communicatively coupled to the excitation source 1118 and is configured to control the excitation source 1118 to cause the ultrasonic transducer 214 to radiate approximately the same amount of acoustic energy when the diameter of the body cavity (e.g., renal artery) is within a specified diameter range (at least 4 mm or at least 5 mm). An example of the specified diameter range is approximately 3.0 mm to approximately 8.0 mm, but is not limited to this.

[0136] In certain embodiments, a specified diameter range, which is at least 4 mm or at least 5 mm, includes a lower limit (lower end) and an upper limit (upper end) of the specified diameter range. In certain embodiments, the lower limit of the specified diameter range is about 2.0 mm, about 2.5 mm, or about 3.0 mm, and the upper limit of the specified diameter range is about 7.5 mm, about 8.0 mm, or about 8.5 mm. Thus, the specified diameter range may be, for example, about 2.0 mm to about 7.5 mm, about 2.0 mm to about 8.0 mm, about 2.0 mm to about 8.5 mm, about 2.5 mm to about 7.5 mm, about 2.5 mm to about 8.0 mm, about 2.5 mm to about 8.5 mm, about 3.0 mm to about 7.5 mm, about 3.0 mm to about 8.0 mm, or about 3.0 mm to about 8.5 mm. Other variations are also possible and are within the scope of the embodiments described herein. Where used to specify values ​​in this specification, the term "approximately" means a value within ±10 percent of that value. For example, "approximately 3 mm" means a range of 3 mm ± 0.3 mm, and "approximately 8 mm" means a range of 8 mm ± 0.8 mm.

[0137] The amount of acoustic energy radiated by the ultrasonic transducer 214 and entering the target tissue surrounding the body cavity in which the ultrasonic transducer 214 is located is equal to the product of the duration (T) during which the acoustic signal is radiated and the acoustic penetration power. The acoustic penetration power can be based on (and depend on) various factors, including the output power level setting of the excitation source (e.g., 1118), the power efficiency of the system (including its components), the frequency of the acoustic signal emitted by the ultrasonic transducer 214, the duration (T) of the acoustic signal emitted by the ultrasonic transducer, and the amount of attenuation caused by the medium between the ultrasonic transducer and the body cavity wall. If the ultrasonic transducer 214 is located within a balloon 108 through which a cooling fluid (e.g., water, sterile water, saline solution, or D5W) is circulated, the cooling fluid and the balloon material (and possibly the folds of the balloon material) are the medium between the ultrasonic transducer 214 and the body cavity wall. If the catheter is balloonless (i.e., does not have a balloon), blood passing through the body cavity is the medium between the ultrasonic transducer and the body cavity wall. The catheter may include a centering mechanism configured to roughly center the ultrasonic transducer within the body cavity. In certain embodiments, the centering mechanism is provided by a compliant balloon 108. Alternatively or additionally, the centering mechanism may include, but is not limited to, one or more flexible baskets attached to the catheter shaft (e.g., 212), or other structures such as a helical spring.

[0138] In other words, the total energy absorbed by the target patient tissue (also called the target tissue, target zone, or target region) surrounding the body cavity (where the ultrasound transducer 214 is positioned) is E eff ) is the acoustic entry energy (E O This is the product of ) multiplied by the percentage (β) (e.g., percent) of energy used for ablation in the target region. Here, the percentage (β) (e.g., percent) of energy used for ablation in the target region depends on the degree of attenuation caused by the medium between the ultrasonic transducer and the body cavity wall. More specifically, Eeff = β·E O = (1 - e -2αfd )P O It is T, where a is the attenuation coefficient (neper / MHz / cm), β is the ratio of the energy used for ablation in the target region (e.g., percentage), f is the acoustic frequency, and d is the desired outer lesion boundary (also called the depth of the lesion). The total energy (E eff ) absorbed in the target region can also be referred to here as the effective energy (E eff ).

[0139] The acoustic input energy (E O ) is the sum of the acoustic power delivered to the patient's tissue through, for example, the balloon wall. As the sound wave propagates through the patient's tissue, the acoustic power is attenuated and converted into heat, resulting in a temperature rise in the tissue. Only a part (β) (e.g., percentage) of the acoustic input energy (E O ) is absorbed in the target region, and the remaining part further propagates and is absorbed by the non-target patient tissue beyond the target region. Just in case, energy (e.g., acoustic input energy, E O ) is the product of power (e.g., acoustic input power, P O ) and time (also referred to as the duration). Therefore, the effective energy (E eff ) (the ratio of the acoustic energy absorbed by the target region) is equal to the product of β and the acoustic input energy (E O ), that is, as described above, E eff = β·E O . The value of β can depend on various different parameters such as the acoustic frequency f and the desired lesion depth d (but not limited to these).

[0140] To maintain the same lesion boundary d (also called the lesion depth), E effThis must be kept constant. This statement applies when the treatment time (also called duration) T does not change significantly, and when the effects of heat conduction do not change significantly. It should be noted that if the treatment time (also called duration) T is greatly increased to compensate for heat loss due to heat conduction, more total energy or effective energy is generally required. Table 3 below shows the acoustic penetration power at various different ultrasound frequencies, assuming a desired lesion depth (d) of 4 mm and a treatment time (T) of 7 seconds. [Table 3] TIFF2026516145000004.tif33155

[0141] Table 4 below shows the acoustic penetration power at various different ultrasound frequencies, assuming a desired lesion depth (d) of 6 mm and a treatment time (T) of 7 seconds. As can be seen from the comparison between Table 4 and Table 3, a higher acoustic penetration power of 35.6 W should be used when a lesion depth of 6 mm is desired, compared to the 26.0 W acoustic penetration power that may be used when a desired lesion depth of 4 mm (more distal, i.e., closer to the kidney, may be more appropriate). [Table 4] TIFF2026516145000005.tif33155

[0142] Table 5 below shows the acoustic penetration power at various different ultrasound frequencies, assuming a desired lesion depth (d) of 6 mm and a treatment time (T) of 10 seconds. As can be seen from the comparison between Table 5 and Table 4, a lower acoustic penetration power of 24.2 W should be used when it is desired to produce a lesion depth of 6 mm when the acoustic penetration power is supplied for a duration of 10 seconds, compared to 36.4 W of acoustic penetration power that can be supplied for a shorter duration of 7 seconds to produce the same desired lesion depth of 6 mm. [Table 5] TIFF2026516145000006.tif33155

[0143] In a particular single-power embodiment, the controller 104 is configured to control the excitation source (when the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within a specified diameter range) to cause the ultrasonic transducer 214 to radiate approximately the same amount of acoustic energy, resulting in approximately the same output power level setting, approximately the same frequency of the acoustic energy radiated by the transducer 214 (e.g., approximately 9 MHz), and approximately the same duration of the acoustic energy radiated by the transducer 214 (e.g., approximately 7 seconds). In a particular such embodiment, the frequency of the acoustic energy is approximately 9 MHz, the duration of the acoustic power supply is approximately 7 seconds, and the acoustic entry power is approximately 34.6 W. In a particular single-power embodiment, the catheter 102 includes a balloon 108 in which the ultrasonic transducer 214 is located, and the balloon 108 may be a compliant balloon. Exemplary details of the balloon 108 have been described above with reference to Figures 5 to 9. In other single-power embodiments, the catheter is balloonless.

[0144] The values ​​shown in Tables 3, 4, and 5 are exemplary values ​​for a tissue treatment system 100 in which an ultrasonic transducer 214 is positioned within a balloon 108 through which a cooling fluid is circulated. As previously mentioned, when the catheter is balloonless (i.e., without a balloon), the blood flowing through the body cavity is the medium between the ultrasonic transducer and the body cavity wall. In contrast, when the catheter includes a balloon 108 in which the ultrasonic transducer 214 is positioned, the medium between the ultrasonic transducer 214 and the body cavity wall is the cooling fluid (circulated through the balloon 108) and the balloon material (the material of the balloon 108). Because the decay coefficient of blood is greater than that of a typical cooling fluid (e.g., at least 10 times greater), the values ​​shown in Tables 3, 4, and 5 differ in the balloonless embodiment.

[0145] If the catheter includes a balloon 108 in which an ultrasonic transducer 214 is placed, the tissue treatment system 100 may also include a fluid supply subsystem 1130 configured to circulate a cooling fluid through the balloon 108, and the controller 104 may be configured to control the fluid supply subsystem 1130. In such a system, the amount of acoustic entry power is also based on the flow rate of the cooling fluid circulating through the balloon 108. In a particular single-power embodiment, the controller 104 may be configured to control the fluid supply subsystem 1130 such that the flow rate of the cooling fluid circulating through the balloon is the same when the diameter of the body cavity is within a specified diameter range (e.g., about 3 mm to about 8 mm). The flow rate of the cooling fluid circulating through the balloon 108 may be, for example, in a flow rate range of about 5 mL / min to about 40 mL / min, and in a particular embodiment, in a flow rate range of about 10 mL / min to about 15 mL / min. Unless otherwise specified, the temperature of the cooling fluid is assumed to be the room temperature of the room in which the tissue treatment system 100 is installed, however, the temperature of the cooling fluid may be changed as needed, for example, by using a cooling element.

[0146] It has been found to be advantageous to configure the controller 104 to control the fluid supply subsystem 1130 to circulate fluid through the balloon 108 for a predetermined time after at least a first amount of energy has been radiated by the ultrasonic transducer 214. Once energy radiation has stopped, the fluid supply subsystem 1130 may continue to operate for a predetermined time to ensure efficient cooling and avoid undesirable clinical outcomes (e.g., with respect to lesion depth). The predetermined time may be in the range of 0.5 to 20 seconds, for example, in the range of 2 to 12 seconds, and especially in the range of 5 to 9 seconds. While such “post-radiation cooling” is particularly useful for system operation in the lower subrange, the controller 104 may also be configured to control the fluid supply subsystem 1130 to circulate fluid through the balloon 108 for a predetermined time after at least a second amount of energy has been radiated by the ultrasonic transducer 214 (i.e., during system operation in the upper subrange). Once energy radiation in the upper subrange has stopped, the fluid supply subsystem 1130 may continue to operate for a predetermined time. The specified time could be in the range of 0.5 to 20 seconds, for example, in the range of 2 to 12 seconds, and especially in the range of 5 to 9 seconds. Such "post-radiation cooling" can also be applied in the context of a single-power strategy (mode).

[0147] Figure 12A is a graph showing the relationship between acoustic entry power in watts (W) and cavity size in millimeters (mm), corresponding to an exemplary embodiment of a single-power embodiment. The straight line 1202 in Figure 12A indicates that the acoustic entry power (W) is approximately the same over a cavity diameter range of approximately 3.0 mm to approximately 8.0 mm, and the dashed line 1204 corresponds to a variation of + / - 10%. It can be said that the acoustic entry power remains approximately the same (more specifically, remains approximately 34.6 W) as long as it is within the range of the dashed line 1204 (taking into account uncertainties such as tolerances).

[0148] Figure 12B is a graph showing the relationship between acoustic entry power in watts (W) and cavity size in millimeters (mm), corresponding to another exemplary embodiment of the single-power embodiment. Curve 1212 in Figure 12B shows that the acoustic power may be somewhat lower for smaller cavity diameters than for larger cavity diameters over a range of cavity diameters from approximately 3.0 mm to approximately 8.0 mm, and the dashed line 1214 corresponds to a variation of + / -10%. In the graph of Figure 12B, it is assumed that the ultrasonic transducer 214 is placed inside a compliant balloon 108, for example, inside a balloon made of pelletan having a Shore D durometer hardness of 55, a nominal balloon diameter (e.g., 6.5 mm), and a corresponding nominal balloon wall thickness. According to certain embodiments, a compliant balloon as disclosed in U.S. Patent Application No. 17 / 812,884, entitled “Catheter Having a Compliant Balloon,” filed July 15, 2022 (publication number US 2023 0026169), may also be used. That document is incorporated herein by reference. According to certain embodiments, a balloon may be used that includes, for example, a plurality of helical folds extending around an ultrasonic transducer between a proximal and distal balloon end, as disclosed in U.S. Patent Provisional Application No. 63 / 482,463, entitled “Tissue Therapy Catheter Having a Torsional Member,” filed January 31, 2023, and is held in place by a torsional member.

[0149] In Figure 12B, due to one or more folds in the compliant balloon 108, the acoustic power may be lower as the diameter of the body cavity decreases. These one or more folds are present when the compliant balloon 108 is partially inflated and its diameter is smaller than the nominal balloon diameter of the compliant balloon 108 (e.g., 6.5 mm), and at least partially attenuate a portion of the acoustic power radiated by the ultrasonic transducer 214. This can reduce the amount of acoustic power passing through the balloon 108 when the diameter of the adjacent body cavity to the compliant balloon 108 is within a smaller diameter subset (e.g., approximately 3.0 mm to approximately 6.5 mm) of a specified diameter range (e.g., approximately 3.0 mm to approximately 8.0 mm), compared to when the compliant balloon 108 is inflated to at least its nominal balloon diameter (e.g., 6.5 mm) and the diameter of the adjacent body cavity to the compliant balloon 108 is within a larger diameter subset (e.g., approximately 6.5 mm to approximately 8 mm) of the specified diameter range (e.g., approximately 3.0 mm to approximately 8.0 mm). More specifically, the aforementioned folds (e.g., wrinkles) of the compliant balloon 108 can increase the reflection and / or scattering of the ultrasonic signal emitted by the ultrasonic transducer 214, which increases the propagation distance the ultrasonic signal travels before leaving the balloon 108 and entering the target tissue surrounding the body cavity. Furthermore, the fold effectively increases the thickness of the balloon in the area where the fold (e.g., wrinkle) is present. Since the thickness of the balloon material affects the amount of attenuation produced by the balloon (i.e., the thicker the balloon material, the greater the attenuation), the effective increase in balloon thickness due to the fold also contributes to the attenuation of acoustic power. These two factors result in a higher rate of acoustic energy loss before the acoustic power is transmitted to the target tissue compared to using a balloon of the same size but without a fold (e.g., wrinkle). Examples of folds (e.g., wrinkles) in the compliant balloon 108 are illustrated in Figures 8A to 8F and have been described above with reference to them. Certain embodiments utilize the fold to help deliver an appropriate amount of acoustic power to the tissue to be treated.

[0150] More generally, folds within the compliant balloon 808 (e.g., 800, 808, and / or 822, but not limited to these), which exist when the compliant balloon is partially inflated and its diameter is smaller than the nominal balloon diameter of the compliant balloon, are configured to attenuate the acoustic power radiated by the ultrasonic transducer more than other acoustic powers, thereby allowing less acoustic power to pass through the compliant balloon 108 when the compliant balloon is adjacent to a cavity segment with a diameter within a smaller diameter subset of the specified diameter range (e.g., less than 5 mm) compared to when the compliant balloon is adjacent to a cavity segment with a diameter within a larger diameter subset of the specified diameter range (e.g., 5 mm or more).

[0151] In certain embodiments, when the compliant balloon 108 is inflated beyond its nominal balloon diameter (e.g., about 6.5 mm), the compliant balloon 108 stretches, and its balloon wall thickness becomes thinner than the nominal balloon wall thickness. This can result in less attenuation of the acoustic power radiated by the ultrasonic transducer 214 when the diameter of the adjacent body cavity to which the compliant balloon 108 is located is within a larger diameter subset of the specified diameter range, compared to when the diameter of the adjacent body cavity to which the compliant balloon 108 is located is within a smaller diameter subset of the specified diameter range. In other words, another reason why the acoustic power entering a larger body cavity may be greater than that entering a smaller body cavity is that the balloon wall thickness may decrease as the balloon is inflated, and thinner walls result in less attenuation of acoustic power.

[0152] Figure 13A is a graph showing the relationship between acoustic entry power in watts (W) and cavity size in millimeters (mm), corresponding to exemplary implementations of two power embodiments. The stepped line 1302 in Figure 13A indicates that the acoustic entry power (W) is generally of a first magnitude (e.g., approximately 32.0 W) when the cavity diameter is in the lower sub-range of approximately 3.0 mm to approximately 4.9 mm, and generally of a second magnitude (e.g., approximately 35.8 W) when the cavity diameter is in the upper sub-range of approximately 5.0 mm to approximately 8.0 mm. The dashed line 1304 corresponds to a variation of + / - 10% (e.g., considering uncertainties such as tolerances).

[0153] Figure 13B is a graph showing the relationship between acoustic entry power in watts (W) and cavity size in millimeters (mm), corresponding to another exemplary implementation of the two power embodiments. Curve 1312 in Figure 13B shows that in the lower sub-range of diameters from approximately 3.0 mm to approximately 4.9 mm, the acoustic power may be somewhat lower for smaller cavity diameters than for larger cavity diameters, and also somewhat lower for smaller cavity diameters than for larger cavity diameters in the upper sub-range of diameters from approximately 5.0 mm to approximately 8.0 mm. The dashed line 1314 corresponds to a variation of + / -10%. In the graph of Figure 13B, it is assumed that the ultrasonic transducer 214 is placed inside a compliant balloon 108 having a nominal balloon diameter (e.g., 6.75 mm) and a corresponding nominal balloon wall thickness.

[0154] For the same reasons as previously stated with reference to Figure 12B, one or more folds in the compliant balloon 108 may result in lower acoustic power in the lower sub-range of diameters from approximately 3.0 mm to approximately 4.9 mm compared to larger body cavity diameters. This is because the one or more folds are present when the compliant balloon 108 is partially inflated and its diameter is smaller than the nominal balloon diameter of the compliant balloon 108 (e.g., 6.5 mm), and at least partially attenuate a portion of the first quantity of acoustic power radiated by the ultrasonic transducer 214. Similarly, one or more folds in the compliant balloon 108 may also result in lower acoustic power in the upper sub-range of diameters from approximately 5.0 mm to approximately 8.0 mm compared to larger body cavity diameters. The one or more folds are present when the compliant balloon 108 is partially inflated and its diameter is smaller than the nominal balloon diameter of the compliant balloon 108 (e.g., 6.5 mm), and at least partially attenuate a portion of the second quantity of acoustic power radiated by the ultrasonic transducer 214. This is because, as previously stated, the folds may increase the reflection and / or scattering of the ultrasonic signal radiated by the ultrasonic transducer 214, which increases the propagation distance the ultrasonic signal travels before leaving the balloon 108 and entering the target tissue surrounding the body cavity. Furthermore, the folds effectively increase the thickness of the balloon in the portion where the fold (e.g., wrinkle) is present. Another reason why the acoustic penetration power may be greater for larger body cavity sizes than for smaller body cavity sizes, as previously stated, is that the balloon wall thickness may decrease as the balloon is inflated beyond its nominal expansion diameter, and thinner walls result in less attenuation of acoustic power.

[0155] Figure 13C is a graph showing the relationship between acoustic entry power in watts (W) and cavity size in millimeters (mm), corresponding to yet another exemplary implementation of the two power embodiments. The bold curve 1322 in Figure 13C shows that in the lower sub-range of diameters from approximately 3.0 mm to approximately 4.9 mm, the acoustic power may be somewhat lower for smaller cavity diameters than for larger cavity diameters, and also somewhat lower for smaller cavity diameters than for larger cavity diameters in the upper sub-range of diameters from approximately 5.0 mm to approximately 8.0 mm. In the graph of Figure 13C, it is assumed that the ultrasonic transducer 214 is placed inside a compliant balloon 108 having a nominal balloon diameter (e.g., 6.5 mm) and a corresponding nominal balloon wall thickness.

[0156] For the same reasons as previously stated with reference to Figures 12B and 13B, one or more folds in the compliant balloon 108 can result in lower acoustic power for smaller cavity diameters than for larger cavity diameters in the lower sub-range of approximately 3.0 mm to approximately 4.9 mm in diameter (e.g., with respect to patient entry power at a constant nominal power setting by the controller 104). This is because the one or more folds are present when the compliant balloon 108 is partially inflated and its diameter is smaller than the nominal balloon diameter of the compliant balloon 108 (e.g., 6.5 mm), and at least partially attenuates a portion of the first amount of acoustic power radiated by the ultrasonic transducer 214. Similarly, one or more folds in the compliant balloon 108 can also result in lower acoustic power for smaller cavity diameters than for larger cavity diameters in the upper sub-range of approximately 5.0 mm to approximately 8.0 mm in diameter (e.g., with respect to patient entry power at a constant nominal power setting by the controller 104). The one or more folds are present when the compliant balloon 108 is partially inflated and its diameter is smaller than the nominal balloon diameter of the compliant balloon 108 (e.g., 6.5 mm), and at least partially attenuates a portion of the second quantity of acoustic power radiated by the ultrasonic transducer 214. For comparative purposes, the dashed line 1330 shows the power curve (e.g., with respect to the nominal power setting by the controller 104) when the attenuation (and possibly further attenuation) caused by the aforementioned “fold effect” is not considered. As is evident from the comparison between the solid line 1322 and the dashed line 1330, the folds (e.g., wrinkles 800) disappear when the nominal balloon diameter is reached during inflation of the balloon 108, and therefore the “fold effect” is more significant when the size of the body cavity (and the diameter of the inflated balloon) is less than the nominal balloon diameter (here, 6.5 mm). In practice, it has been found that it is advantageous to select a nominal balloon diameter that is larger than the designated intermediate diameter (5 mm in this case) that separates the lower and upper sub-ranges.

[0157] Figure 13C also shows a comparison of the two power strategies described above with six more complex power strategies using six different catheters. In Figure 13C, the fine solid line 1324 shows the acoustic power output by each of the six catheters, each specifically designed for six particular body cavity sizes and having (non-compliant) balloon diameters of 3.5 mm, 4.2 mm, 5.0 mm, 6.0 mm, 7.0 mm, and 8.0 mm when inflated to their maximum size (e.g., with respect to acoustic patient power). The dotted line 1326 and dashed line 1328 show the power uncertainty in acoustic power output for the two power strategies (line 1322) and the six power strategies (line 1324), respectively. These uncertainties are due to system-specific tolerances (e.g., excitation source) and other influences. As is evident from the dotted line 1326 and dashed line 1328, it was found that by implementing slightly stricter tolerance controls for the two power strategies, the (smaller) uncertainty resulting from the two power strategies could be maintained within the power envelope of the six power strategies, thereby ensuring consistent clinical outcomes (in terms of safety and efficacy).

[0158] As is further evident from dotted lines 1326 and dashed lines 1328 illustrating the uncertainties between the two power strategies and the six power strategies, attenuation due to the "fold effect" is very helpful in ensuring that the acoustic entry power (including its inherent uncertainty) of the two power strategies does not exceed the power envelope of the (well-tested) six power strategies, especially for smaller cavity sizes within the lower and upper subranges. If the "fold effect" were absent in the two power strategies (see dashed line 1330 illustrating the two power approaches without attenuation due to the fold), the acoustic power (with its inherent uncertainty, but not illustrated in Figure 13C) would be too high (assuming the remaining parameters, such as the frequency and duration of energy emission, are constant), especially in the smaller vascular size regions within the lower and upper subranges. These results demonstrate that the two power strategies are indeed a practical solution (for example, because consistent lesion depth, and therefore consistent clinical outcomes, can be guaranteed).

[0159] The overall power uncertainty, or tolerance, is defined by two main factors: the power tolerance of the excitation source (also called the "generator") and the uncertainty caused by the acoustic efficiency of the catheter. The accuracy of the power measurement may also need to be considered. It has been found that the power tolerance of the excitation source contributes most significantly to the overall power uncertainty. In the low-power setting of 10 watts for a conventional excitation source, the power tolerance may be in the range of + / -25%, but can decrease in higher power settings. In the power settings of approximately 25-35 watts commonly proposed herein, the power tolerance will be in the range of + / -13%. Thus, for the two power strategies, power tolerances of less than + / -12%, and especially less than + / -10% or + / -8%, can be implemented. Such relatively tight tolerance control is possible, for example, by using higher quality components (e.g., with respect to the excitation source) and power control loops. Taking into account the overall power uncertainty (including uncertainty caused by the acoustic efficiency of the catheter and potential uncertainty in power measurement), power tolerances of less than + / -26%, and especially less than + / -21% or + / -16%, can be achieved.

[0160] From the perspective of the desired "crease effect," it may be advantageous not to reduce the tolerance below a certain threshold so that power fluctuations resulting from a certain randomness in how and where the creases are positioned and unfolded can still be absorbed. Despite the apparent randomness with respect to the creases (e.g., when they take the form of wrinkles), it was found that there is a predictable, roughly linear relationship between the "attenuation of acoustic power due to the creases" and the "degree of creasing," where the "degree of creasing" can be mathematically defined as ((nominal balloon diameter / inflated balloon diameter - 1) × 100%). When the inflated balloon diameter is greater than the nominal balloon diameter, the "degree of creasing" is defined as zero. The attenuation of acoustic power can be defined as (1 - measured acoustic power / expected acoustic power without wrinkles) × 100%. The expected acoustic power was derived from the average of repeated measurements using a creaseless balloon, and the measured acoustic power was measured using a similar balloon with creases. Furthermore, it was found that the residual randomness in the power distribution caused by the folds is compensated for by heat conduction within the tissue. These results provide a consistent physical foundation for the two power strategies.

[0161] As is evident from Figure 13C, the contribution of the combination of particularly strict power control and the "fold effect" paves the way for the two power strategies. The dotted and dashed lines 1326 and 1328, which show the uncertainty between the two power strategies and the six power strategies, further demonstrate that it is indeed beneficial to select a nominal balloon diameter (here 6.5 mm) that is larger than the specified intermediate diameter (here 5 mm) that separates the lower and upper subranges, respectively. Such a selection helps ensure that the tolerance of the two power strategies remains within the power uncertainty envelope of the six power strategies.

[0162] In the two power strategies, it is advantageous to select a first quantity of acoustic energy based on an acoustic input power in the first range of approximately 25.0, 27.5, or 30.0 watts to approximately 33.0 watts, and a second quantity of acoustic energy based on an acoustic input power in the second range of approximately 32.0 or 33.1 watts to approximately 39.0 watts. The duration of power supply in the lower subrange may be selected such that the first quantity of acoustic energy is in the range of 140 J to 240 J, or 165 J to 215 J (e.g., approximately 190 J). The duration of power supply in the upper subrange may be selected such that the second quantity of acoustic energy is in the range of 180 J to 270 J, or 200 J to 250 J (e.g., approximately 225 J). In these examples, the generator frequency may be set to approximately 9 MHz. At higher frequencies of approximately 12 MHz, the energy is reduced by approximately 15-25%, while at lower frequencies of approximately 6 MHz, the energy is increased by approximately 20-35%. In all variations described herein, energy measurements may be performed in accordance with IEC 61161 Edition 3.0,2013-01 or BS EN 62555:2014.

[0163] According to a particular embodiment, the controller 104 is configured to automatically determine an estimate of the body cavity diameter using, for example, one of the techniques disclosed in U.S. Patent Application No. 17 / 812,973 (Publication No. US 2023 0026504), titled “Method and System for Determining Body Cavity Size,” filed and jointly assigned on 15 July 2022. That document is incorporated herein by reference. Furthermore, the controller 104 is configured to control the excitation source 1118 to cause the ultrasonic transducer 214 to emit a first quantity of acoustic energy based on the determination that the estimate of the body cavity diameter is within a lower sub-range of a specified diameter range, and to control the excitation source 1118 to cause the ultrasonic transducer 214 to emit a second quantity of acoustic energy based on the determination that the estimate of the body cavity diameter is within an upper sub-range of a specified diameter range.

[0164] In certain embodiments, the user interface 1116 of the system 100 allows the user to specify whether the diameter of a body cavity is within a lower sub-range of a specified diameter range or within an upper sub-range of a specified diameter range. An example of such a user interface 1116 is shown in Figure 14. In one embodiment, the user interface 1116 is further configured to display a warning message when the automatically determined estimate of the body cavity diameter is not within the sub-range entered by the user. The user interface 1116 may also be configured to allow the user to specify the type of body cavity. For example, the controller may store in memory 1114 several different types of body cavities and whether each type of body cavity is within a lower sub-range of a specified diameter range or within an upper sub-range of a specified diameter range. Several different types of body cavities may include, but are not limited to, the main renal artery, adrenal artery, and renal artery branches. In certain such embodiments, the controller 104 is further configured to control the excitation source 1118 to cause the ultrasonic transducer 214 to emit a first amount of acoustic energy when the user interface 1116 specifies that the diameter of the body cavity is within a lower sub-range of a specified diameter range, and to control the excitation source 1118 to cause the ultrasonic transducer 214 to emit a second amount of acoustic energy when the user interface 1116 specifies that the diameter of the body cavity is within an upper sub-range of a specified diameter range. The user interface 1116 may also be configured to display a warning message when the automatically determined estimate of the body cavity diameter is not within a sub-range entered by the user.

[0165] Figure 15 is a high-level flowchart illustrating an overview of a single-power scheme for use in a tissue treatment system comprising a catheter 102 including a distal portion (e.g., shaft 212) in which an ultrasonic transducer 214 is located. Referring to Figure 15, step 1502 includes inserting the distal portion of the catheter 102 into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm, thereby positioning the ultrasonic transducer within a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm. For example, the diameter range may be, but is not limited to, about 3.0 mm to about 8.0 mm. Further details of such a range have been described above and will not be repeated. Step 1504 includes causing the ultrasonic transducer 214 to radiate about the same amount of acoustic energy when the diameter of the segment of the body cavity is within a specified diameter range of at least 5 mm, for example, within the range of about 3.0 mm to about 8.0 mm. Exemplary amounts of acoustic energy that may be used in a single-power embodiment have been described above and will not be repeated.

[0166] As described above, the distal portion of the catheter 102 may include a compliant balloon 108 in which an ultrasonic transducer 214 is disposed, and the compliant balloon 108 is configured to include one or more folds when the compliant balloon 108 is partially inflated and its diameter is smaller than the nominal balloon diameter. Several examples of this have been described above. In such embodiments, the method may also include the step of inflating the compliant balloon 108 so that the compliant balloon is adjacent to (juxtaposed with) the cavity wall of the cavity segment in which the ultrasonic transducer 214 is disposed. The method may also include a step of utilizing one or more folds within the compliant balloon to at least partially attenuate a portion of the acoustic power radiated by the ultrasonic transducer 214, thereby reducing the amount of acoustic power passing through the compliant balloon 108 when the diameter of the adjacent body cavity segment is within a smaller diameter subset of a specified diameter range compared to when the compliant balloon is inflated to at least the nominal balloon diameter of the compliant balloon and the diameter of the adjacent body cavity segment is within a larger diameter subset of a specified diameter range.

[0167] Figure 16 is a high-level flowchart illustrating two power schemes for use in a tissue treatment system comprising a catheter 102 including a distal portion (e.g., shaft 212) in which an ultrasonic transducer 214 is located. Referring to Figure 16, step 1602 includes inserting the distal portion of the catheter 102 into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm, thereby positioning the ultrasonic transducer within a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm. For example, the diameter range may be, but is not limited to, about 3.0 mm to about 8.0 mm. Further details of such a range have been described above and will not be repeated. Step 1604 includes determining whether the diameter of the segment of the body cavity in which the ultrasonic transducer 214 is located is within a lower sub-range of the specified diameter range or within an upper sub-range of the specified diameter range. For example, the lower subrange may be approximately 3.0 mm to 4.9 mm, and the upper subrange may be approximately 5.0 mm to 8.0 mm, but is not limited thereto. In another example, the lower subrange may be approximately 3.0 mm to 4.5 mm, and the upper subrange may be approximately 4.6 mm to 8.0 mm, but is not limited thereto. Further details of such ranges and subranges have been described above and will not be repeated. Next, the determination in step 1606 is made, and as a result, the flow proceeds to either step 1608 or step 1610. Step 1608 includes the step of causing the ultrasonic transducer to emit a first amount of acoustic energy when it is determined that the diameter of the segment of the body cavity in which the ultrasonic transducer 214 is located is within the lower subrange of a specified diameter range (e.g., approximately 3.0 mm to 4.9 mm). In contrast, step 610 includes the step of causing the ultrasonic transducer to emit a second quantity of acoustic energy (greater than the first quantity of acoustic energy) when it is determined that the diameter of the segment of the body cavity in which the ultrasonic transducer 214 is located is within an upper sub-range of a specified diameter range (e.g., about 5.0 mm to about 8.0 mm).

[0168] According to a particular embodiment, the determination in step 1604 (whether the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within a lower sub-range of a specified diameter range or within an upper sub-range of a specified diameter range) is determined by the user (e.g., using fluoroscopy or other visualization techniques) and input by the user into the tissue treatment system using the user interface of the tissue treatment system (e.g., 1116). An example of such a user interface is illustrated in Figure 14, which has been described above.

[0169] According to a particular embodiment, the determination in step 1604 (determining whether the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within a lower sub-range of a specified diameter range or within an upper sub-range of a specified diameter range) is determined by receiving an indication (indicator) from the user via a user interface (e.g., 1116) that the ultrasonic transducer is located in one of several different types of body cavities. Then, based on the indication (indicator) received via the user interface, it is determined whether the diameter of the segment of the body cavity (in which the ultrasonic transducer is located) is within a lower sub-range of a specified diameter range or within an upper sub-range of a specified diameter range. Several different types of body cavities may include, but are not limited to, the main renal artery, the adrenal artery, and the renal artery branches.

[0170] According to certain embodiments, the determination in step 1604 (determining whether the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within a lower sub-range of a specified diameter range or within an upper sub-range of a specified diameter range) may be automatically determined by the tissue treatment system using, for example, one of the techniques disclosed in U.S. Patent Application No. 17 / 812,973, published in July 15, 2022, entitled “Method and System for Determining Body Cavity Size.” This document is incorporated herein by reference.

[0171] As described above, the distal portion of the catheter 102 may include a compliant balloon 108 in which an ultrasonic transducer 214 is disposed, and the compliant balloon 108 is configured to include one or more folds when the compliant balloon 108 is partially inflated and its diameter is smaller than the nominal balloon diameter. Several examples of this have been described above. In such embodiments, the method may also include the step of inflating the compliant balloon 108 so that the compliant balloon is adjacent to (juxtaposed with) the cavity wall of the cavity segment in which the ultrasonic transducer 214 is disposed. The method may also include a step of utilizing one or more folds within the compliant balloon to at least partially attenuate a portion of the acoustic power radiated by the ultrasonic transducer 214, thereby reducing the amount of acoustic power passing through the compliant balloon 108 when the diameter of the adjacent body cavity segment is within a smaller diameter subset of a specified diameter range compared to when the compliant balloon is inflated to at least the nominal balloon diameter of the compliant balloon and the diameter of the adjacent body cavity segment is within a larger diameter subset of a specified diameter range.

[0172] The body cavities in which the methods described with reference to Figures 15 and 16 can be used may be, but are not limited to, the renal arteries. For example, the body cavities may be one of the following: veins, pulmonary arteries, vascular cavities, celiac arteries, common hepatic arteries, proper hepatic arteries, gastroduodenal arteries, hepatic arteries, splenic arteries, gastric arteries, blood vessels, nonvascular cavities, airways, sinuses, esophagus, respiratory cavities, digestive cavities, stomach, duodenum, jejunum, or cancerous tissue.

[0173] According to a particular embodiment, the body cavity into which the catheter of the aforementioned system is inserted, and which is used to denervate nerves in the tissue surrounding the body cavity, is the renal artery, and such nerves include the renal nerves that supply the kidneys. When the neurodemission surgery described herein is performed using a catheter inserted into a renal artery type body cavity (e.g., 102), the disease treated using such neurodemission surgery may be hypertension or other diseases associated with increased sympathetic nerve activity, as can be understood from the foregoing description. However, the embodiments of the art described herein may also be used to perform neurodemission surgery (and / or other tissue treatment surgery) using a catheter inserted into a different type of body cavity other than the renal artery to treat other types of diseases other than hypertension. For example, other types of body cavities include, but are not limited to, veins, pulmonary arteries, vascular cavities, celiac arteries, common hepatic arteries, proper hepatic arteries, gastroduodenal arteries, hepatic arteries, splenic arteries, gastric arteries, blood vessels, non-vascular cavities, airways, sinuses, esophagus, respiratory cavities, digestive cavities, stomach, duodenum, jejunum, cancerous tissue, tumors, intestines, and urinary cavities. Examples of other types of diseases that can be treated using embodiments of this technology include, but are not limited to, pulmonary hypertension, diabetes mellitus, obesity, non-alcoholic fatty liver disease, heart failure, end-stage renal disease, gastrointestinal diseases, cancer, tumors, pain, asthma, or chronic obstructive pulmonary disease (COPD). As is evident from the foregoing description, a tissue therapeutic system is presented, particularly in the context of the two power strategies shown in Figure 13C. The system comprises a catheter including a distal portion on which an ultrasonic transducer is located, the catheter being configured such that at least the distal portion of the catheter is insertable into a segment of a body cavity having a diameter within a specified diameter range, the specified diameter range having a lower sub-range and an upper sub-range. The system further comprises an excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, and a controller communicatively coupled to the excitation source, the controller being configured to control the excitation source so that the ultrasonic transducer emits two different amounts of acoustic energy.The two distinct amounts of acoustic energy include a first amount of acoustic energy and a second amount of acoustic energy greater than the first amount of acoustic energy. The controller is configured to control the excitation source to cause the ultrasonic transducer to selectively emit either the first or second amount of acoustic energy when it is determined that the diameter of the segment of the body cavity to be treated is within a lower sub-range or an upper sub-range, respectively.

[0174] The controller may be configured to control the excitation source to cause an ultrasonic transducer to emit a first quantity of acoustic energy when it is determined that the diameter of the body cavity segment to be treated is within a lower sub-range. Similarly, the controller may be configured to control the excitation source to cause an ultrasonic transducer to emit a second quantity of acoustic energy when it is determined that the diameter of the body cavity segment to be treated is within an upper sub-range. In some modifications, the controller may be configured to have an operating mode in which only the first and second quantities of acoustic energy are selectively emitted by the excitation source under the control of the controller, and a third quantity of acoustic energy different from the first and second quantities is not emitted, for example.

[0175] In some variations, only a single type of catheter may be used in this mode of operation. In this case, the same catheter may be used in a single surgery to control the excitation source, such as radiating a first amount of acoustic energy to a first segment of a body cavity and a second amount of acoustic energy to a second segment of the same body cavity or another body cavity in the same patient.

[0176] The controller may further be configured to control the excitation source to cause an ultrasonic transducer to emit a first quantity of acoustic energy when the controller determines, based on at least one of a segment diameter estimate automatically determined by the controller and a user specification via the user interface, that the diameter of a segment in a body cavity is within a lower sub-range of a specified diameter range. Additionally or alternatively, the controller may further be configured to control the excitation source to cause an ultrasonic transducer to emit a second quantity of acoustic energy when the controller determines, based on at least one of a segment diameter estimate automatically determined by the controller and a user specification via the user interface, that the diameter of a segment in a body cavity is within an upper sub-range of a specified diameter range. The user interface may be configured to display a warning message when the automatically determined estimate of the diameter of a segment in a body cavity is not within a sub-range specified via the user interface.

[0177] The distal portion of the catheter may further include a balloon in which an ultrasonic transducer is positioned. The balloon may be configured to roughly center the ultrasonic transducer within the body cavity and to circulate fluid through the balloon to cool at least a portion of the tissue adjacent to the body cavity in which the ultrasonic transducer is positioned.

[0178] The balloon may be or may include a compliant balloon. A compliant balloon may be configured such that it includes one or more folds when partially inflated to a diameter smaller than its nominal balloon diameter. The one or more folds may be configured to at least partially attenuate a portion of the acoustic energy radiated by the ultrasonic transducer. In some embodiments, the folds may be configured such that when the balloon is inserted into a body cavity segment and partially inflated to a diameter smaller than its nominal balloon diameter, the fold surface of the balloon generates additional acoustic reflections compared to when the balloon is inflated to a state with no folds, fewer folds, or smaller folds (for example, when occurring in a predictable manner). The nominal balloon diameter may be in the diameter range of 5.5 mm to 7.5 mm, and in particular may be about 6.5 mm.

[0179] With respect to acoustic patient entry power (i.e., power "behind" the balloon as seen from the transducer), a compliant balloon may be configured such that, at a certain nominal power setting by the controller, the attenuation caused by the fold results in somewhat lower acoustic patient entry power for smaller cavity diameters than for larger cavity diameters within the lower subrange (e.g., diameters of approximately 3.0 mm to 4.9 mm), and also somewhat lower acoustic patient entry power for smaller cavity diameters than for larger cavity diameters within the upper subrange (e.g., diameters of approximately 5.0 mm to 8.0 mm). For example, with a nominal power setting selected within the range of approximately 25 watts to 35 watts for the lower subrange (e.g., approximately 30 watts), the attenuation (e.g., with respect to acoustic patient entry power) may be approximately 5% to 15% lower for smaller cavity diameters than for larger cavity diameters within the lower subrange. For nominal power settings selected within the range of approximately 31 watts to 41 watts for the upper subrange (e.g., approximately 36 watts), attenuation (e.g., with respect to acoustic patient entry power) may be approximately 2% to 10% lower for smaller cavity diameters within the upper subrange than for larger cavity diameters. See also dashed line 1330 and solid line 1322 in Figure 13C for further details.

[0180] The system may include a fluid supply subsystem configured to circulate a fluid through a balloon, and the controller may also be configured to control the fluid supply subsystem. The amount of energy absorbed by the tissue surrounding the segment of the body cavity in which the ultrasonic transducer is located may partially depend on the flow rate of the fluid circulating through the balloon. In such a case, the controller may be configured to control the flow rate of the fluid circulating through the balloon to be within a range of approximately 5 mL / min to approximately 40 mL / min, particularly approximately 10 mL / min to approximately 15 mL / min. The controller may be configured to control the fluid supply subsystem to circulate the fluid through the balloon a predetermined time after a first amount of energy has been radiated by the ultrasonic transducer. This predetermined time may be in the range of 2 seconds to 12 seconds, particularly 5 seconds to 9 seconds.

[0181] A specified intermediate diameter may separate the lower subrange from the upper subrange. The specified intermediate diameter may include one of approximately 4.5 mm, approximately 5.0 mm, or approximately 5.5 mm. The nominal balloon diameter may be selected to be larger than the specified intermediate diameter. For example, the nominal balloon diameter may be selected to be at least 10%, at least 20%, or at least 30% larger than the specified intermediate diameter.

[0182] The lower limit of the specified diameter range may include one of approximately 2 mm, 2.5 mm, or 3.0 mm. The upper limit of the specified diameter range may include one of approximately 7.5 mm, 8.0 mm, or 8.5 mm.

[0183] The second quantity of acoustic energy may be at least 8%, at least 10%, at least 12%, or at least 15% greater than the first quantity of acoustic energy. The first quantity of acoustic energy may be based on a first acoustic signal having a first acoustic frequency, a first acoustic power, and a first duration. The second quantity of acoustic energy may be based on a second acoustic signal having a second acoustic frequency, a second acoustic power, and a second duration. The second acoustic power may be greater than the first acoustic power. The second acoustic power may be at least 8%, at least 10%, at least 12%, or at least 15% greater than the first acoustic power. The first acoustic frequency may be equal to the second acoustic frequency. The first duration may be equal to the second duration. The first and second acoustic powers may be acoustic patient entry powers exhibiting attenuation and possibly further attenuation effects due to the folds in the compliant balloon. Alternatively, the first and second acoustic powers may be nominal acoustic powers set by the controller (i.e., balloon-related attenuation has not yet been considered). The total allowable range for generating the first and second acoustic powers may be less than 15%, less than 11%, or less than 8%.

[0184] The specified diameter range may be at least 4 mm. The controller may be configured to control the excitation source such that an ultrasonic transducer radiates only the two different amounts of acoustic energy.

[0185] The first quantity of acoustic energy can be based on a first acoustic power of approximately 27.5 watts or within a first range of approximately 30.0 watts to approximately 33.0 watts. The second quantity of acoustic energy can be based on a second acoustic power of approximately 33.1 watts to approximately 39.0 watts. For example, the first quantity of acoustic energy can be based on a first acoustic power of approximately 29.0 watts or within a first range of approximately 31.0 watts to approximately 33.0 watts, and the second quantity of acoustic energy can be based on a second acoustic power of approximately 33.1 watts to approximately 38.0 watts. In particular, the first quantity of acoustic energy can be based on a first acoustic power of approximately 30.1 watts or approximately 32.0 watts, and the second quantity of acoustic energy can be based on a second acoustic power of approximately 36.0 watts (e.g., 35.8 watts). The first and second acoustic powers may be either the acoustic patient entry power or the nominal acoustic power set by the controller. See also dashed line 1330 in Figure 13C.

[0186] Furthermore, a method for operating a tissue therapy system is presented, the tissue therapy system comprising a catheter including a distal portion on which an ultrasonic transducer is located, an excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, and a controller communicatively coupled to the excitation source, wherein at least the distal portion of the catheter is insertable into a segment of a body cavity having a diameter within a specified diameter range, the diameter range having a lower sub-range and an upper sub-range, and the controller is configured to control the excitation source such that the ultrasonic transducer emits two different amounts of acoustic energy, the two different amounts of acoustic energy The energy comprises a first amount of acoustic energy and a second amount of acoustic energy greater than the first amount of acoustic energy, and the method comprises the following steps performed by the controller: namely, determining whether the diameter of the segment of the body cavity to be treated is within the lower sub-range or within the upper sub-range; and controlling the excitation source such that the ultrasonic transducer selectively emits the first amount of acoustic energy when it is determined that the diameter of the segment of the body cavity to be treated is within the lower sub-range, or selectively emits the second amount of acoustic energy when it is determined that the diameter of the segment of the body cavity to be treated is within the upper sub-range.

[0187] As mentioned above, when used to specify a value, the term "approximately" means a value within ±10 percent of that value. For example, "approximately 3 mm" means a range of 3 mm ± 0.3 mm, and "approximately 8 mm" means a range of 8 mm ± 0.8 mm.

[0188] While several embodiments and examples are disclosed herein, this application extends beyond the specifically disclosed embodiments to other alternative embodiments and / or their uses, modifications, and equivalents. It is also considered that various combinations or subcombinations of specific features and aspects of the embodiments may be realized and fall within the scope of this disclosure. Therefore, it should be understood that the various features and aspects of the disclosed embodiments may be combined with and substituted for each other to form a changing mode of this disclosure. Accordingly, it is intended that the scope of the invention disclosed herein should not be limited by the specific embodiments described above, but should be determined solely by a fair reading of the subsequent claims.

[0189] While various modifications and alternative forms are possible, specific embodiments are shown in the drawings and described in detail herein. However, it should be understood that this disclosure is not limited to any particular form or method disclosed, but rather encompasses all modifications, equivalents, and alternatives that fall within the spirit and scope of the various embodiments and appended claims described herein. None of the methods disclosed herein need to be performed in the order described.

[0190] In the aforementioned specification, the present invention has been described with reference to specific exemplary embodiments thereof. It is evident that various modifications can be made thereto without departing from the broader spirit and scope of the present disclosure as set forth in the following claims. Accordingly, the specification and drawings should be considered illustrative rather than restrictive.

[0191] The following numbered features (sections) define further embodiments of the present disclosure.

[0192] 1. A catheter including a distal portion on which an ultrasound transducer is located, An excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, A controller communicatively coupled to the excitation source, Equipped with, The catheter is configured such that at least the distal portion of the catheter can be inserted into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm. The controller is configured to control the excitation source such that when the diameter of the segment of the body cavity is within the specified diameter range of at least 4 mm, the ultrasonic transducer emits approximately the same amount of acoustic energy. A tissue treatment system characterized by the following features.

[0193] 2. The specified diameter range, which is at least 4 mm, has a lower limit and an upper limit. The lower limit of the specified diameter range includes one of approximately 2 mm, approximately 2.5 mm, or approximately 3.0 mm. The upper limit of the specified diameter range includes one of approximately 7.5 mm, approximately 8.0 mm, or approximately 8.5 mm. The system described in Feature 1, characterized by the features described above.

[0194] 3. The amount of acoustic energy radiated by the ultrasonic transducer is based on the output power of the excitation source driving the ultrasonic transducer, the frequency of the acoustic signal radiated by the ultrasonic transducer, and the duration of the acoustic signal radiated by the ultrasonic transducer. The controller is configured to control the excitation source such that, when the diameter of the segment of the body cavity is within the specified diameter range of at least 4 mm, the output power is approximately the same, the frequency of the acoustic signal emitted by the ultrasonic transducer is approximately the same, and the duration of the acoustic signal emitted by the ultrasonic transducer is approximately the same, thereby causing the ultrasonic transducer to emit approximately the same amount of acoustic energy when the diameter of the segment of the body cavity is within the specified diameter range. A system according to either feature 1 or 2, characterized by the above.

[0195] 4. The distal portion of the catheter further comprises a centering mechanism configured to approximately center the ultrasonic transducer within the body cavity. A system according to any one of features 1 to 3.

[0196] 5. The distal portion of the catheter further includes a balloon in which the ultrasonic transducer is located. The balloon is configured to roughly center the ultrasonic transducer within the body cavity and to circulate fluid through the balloon to cool at least a portion of the tissue adjacent to the body cavity in which the ultrasonic transducer is positioned. A system according to any one of features 1 to 3.

[0197] 6. Fluid supply subsystem configured to circulate the fluid through the balloon. Furthermore, The controller is configured to also control the fluid supply subsystem, The amount of energy absorbed by the tissue surrounding the body cavity segment in which the ultrasonic transducer is located depends in part on the flow rate of the fluid circulating through the balloon. The controller is configured to control the fluid supply subsystem such that the flow rate of the fluid circulating through the balloon is approximately constant when the diameter of the segment of the body cavity is within the specified diameter range, which is at least 4 mm. The system described in feature 5, characterized by the features described above.

[0198] 7. The flow rate of the fluid circulating through the balloon is within the range of approximately 5 mL / min to approximately 40 mL / min. The system described in feature 6, characterized by the features described above.

[0199] 8. The flow rate of the fluid circulating through the balloon is within the range of approximately 10 mL / min to approximately 15 mL / min. The system described in feature 6, characterized by the features described above.

[0200] 9. The balloon includes a compliant balloon. A system characterized by any one of features 5 to 8.

[0201] 10. The compliant balloon is configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, it contains one or more folds. The system described in feature 9, characterized by the features described below.

[0202] 11. The one or more folds include at least one of a wrinkle, one or more spiral folds, or one or more longitudinal folds. The system described in feature 10, characterized by the above.

[0203] 12. The one or more folds of the compliant balloon that exist when the compliant balloon is partially inflated such that the diameter of the compliant balloon is smaller than the nominal balloon diameter of the compliant balloon at least partially attenuate a portion of the acoustic energy radiated by the ultrasonic transducer, thereby reducing the amount of acoustic energy passing through the compliant balloon when the body cavity adjacent to the compliant balloon has a diameter within a smaller diameter subset of the specified diameter range, compared to when the compliant balloon is inflated to have a diameter of at least the nominal balloon diameter of the compliant balloon and the diameter of the segment of the body cavity adjacent to the compliant balloon is within a larger diameter subset of the specified diameter range. The system according to feature 10 or 11, characterized by the above.

[0204] 13. The compliant balloon has a nominal balloon diameter and a corresponding nominal balloon wall thickness. When the compliant balloon is inflated beyond the nominal balloon diameter, the compliant balloon stretches, and the balloon wall thickness becomes thinner than the nominal balloon wall thickness. As a result, when the diameter of the body cavity adjacent to the compliant balloon falls within a larger diameter subset of the specified diameter range, the attenuation of acoustic energy emitted by the ultrasonic transducer is less compared to when the diameter of the segment of the body cavity adjacent to the compliant balloon falls within a smaller diameter subset of the specified diameter range. A system according to any one of features 9 to 12.

[0205] 14. The compliant balloon is made from at least one of the following materials: nylon, polyether block amide, or thermoplastic polyurethane. A system according to any one of features 9 to 13.

[0206] 15. When the diameter of the segment of the body cavity is based on the acoustic entry power within the specified diameter range, the approximately same amount of acoustic energy radiated by the ultrasonic transducer is within the range of acoustic power of approximately 30.0 watts to approximately 39.0 watts. A system according to any one of features 1 to 14.

[0207] 16. The approximately same amount of acoustic energy radiated by the ultrasonic transducer when the diameter of the segment of the body cavity is within the specified diameter range is based on an acoustic input power within the range of approximately 32.0 watts to approximately 36.0 watts of acoustic power. A system according to any one of features 1 to 14.

[0208] 17. The approximately same amount of acoustic energy radiated by the ultrasonic transducer when the diameter of the segment of the body cavity is within the specified diameter range is based on an acoustic input power within the range of approximately 33.0 watts to approximately 35.0 watts. A system according to any one of features 1 to 14.

[0209] 18. The body cavity includes the renal artery. A system according to any one of features 1 to 17, characterized by the features described herein.

[0210] 19. The body cavity includes one of the following: veins, pulmonary arteries, vascular cavities, celiac arteries, common hepatic arteries, proper hepatic arteries, gastroduodenal arteries, hepatic arteries, splenic arteries, gastric arteries, blood vessels, nonvascular cavities, airways, sinuses, esophagus, respiratory cavities, digestive cavities, stomach, duodenum, jejunum, or cancerous tissue. A system according to any one of features 1 to 17, characterized by the features described herein.

[0211] 20. The acoustic energy is selected to produce lesions having a depth within a range of approximately 2.5 mm to approximately 8 mm. A system according to any one of features 1 to 19.

[0212] 21. The acoustic energy is selected to generate lesions having a depth within a range of approximately 5.5 mm to 6.0 mm. A system according to any one of features 1 to 19.

[0213] 22. The one or more folds of the compliant balloon that exist when the compliant balloon is partially inflated such that the diameter of the compliant balloon is smaller than the nominal balloon diameter of the compliant balloon are configured to attenuate the acoustic energy radiated by the ultrasonic transducer more than the acoustic energy radiated by the ultrasonic transducer is configured to allow less acoustic energy to pass through the compliant balloon when the compliant balloon is adjacent to a cavity segment having a diameter within a smaller diameter subset of the specified diameter range compared to when the compliant balloon is adjacent to a cavity segment having a diameter within a larger diameter subset of the specified diameter range. The system according to feature 10 or 11, characterized by the above.

Claims

1. A catheter including a distal portion on which an ultrasound transducer is located, An excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, A controller communicatively coupled to the excitation source, Equipped with, The catheter is configured such that at least the distal portion of the catheter can be inserted into a segment of a body cavity having a diameter within a specified diameter range. The diameter range has a lower sub-range and an upper sub-range, The controller is configured to control the excitation source such that the ultrasonic transducer radiates two different amounts of acoustic energy. The two distinct amounts of acoustic energy include a first amount of acoustic energy and a second amount of acoustic energy that is greater than the first amount of acoustic energy. The controller is configured to control the excitation source such that the ultrasonic transducer radiates a first amount of acoustic energy into a body cavity having a diameter within the lower sub-range, and a second amount of acoustic energy into a body cavity having a diameter within the upper sub-range. A tissue treatment system characterized by the following features.

2. The controller further, To automatically estimate the diameter of the segment of the body cavity, When the controller estimates that the diameter of the segment of the body cavity is within the lower sub-range of the specified diameter range, the excitation source is controlled to cause the ultrasonic transducer to emit the first amount of acoustic energy, and When the controller estimates that the diameter of the segment of the body cavity is within the upper sub-range of the specified diameter range, the excitation source is controlled to cause the ultrasonic transducer to emit the second amount of acoustic energy. It is configured to perform at least one of the following: The system according to feature 1.

3. The system further comprises a user interface connected to the controller, The controller further, The user interface accepts the selection of either the lower sub-range within the specified diameter range or the upper sub-range within the specified diameter range. When the selection is within the lower sub-range of the specified diameter range, the excitation source is controlled so that the ultrasonic transducer radiates a first amount of acoustic energy. When the selection is within the upper sub-range of the specified diameter range, the excitation source is controlled to cause the ultrasonic transducer to radiate the second amount of acoustic energy. It is configured in such a way The system according to feature 2.

4. The distal portion of the catheter further includes a balloon in which the ultrasonic transducer is located. The balloon is configured to roughly center the ultrasonic transducer within the body cavity and to circulate fluid through the balloon to cool at least a portion of the tissue adjacent to the body cavity in which the ultrasonic transducer is positioned. The system according to any one of claims 1 to 3.

5. The balloon includes a compliant balloon. The system according to feature 4.

6. The compliant balloon is configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, the compliant balloon includes one or more folds. The system according to claim 5, characterized in that it is the same as described in claim 5.

7. The one or more folds are configured to at least partially attenuate a portion of the acoustic energy radiated by the ultrasonic transducer. The system described in claim 6.

8. The aforementioned folds are configured such that when the balloon is inserted into a body cavity segment and partially inflated to a size smaller than its nominal balloon diameter, the fold surface of the balloon generates additional acoustic reflections compared to when the balloon is inflated to a state with no folds, fewer folds, or smaller folds. The system according to feature 7.

9. The nominal balloon diameter is within the range of 5.5 mm to 7.5 mm, and is particularly close to 6.5 mm. The system according to any one of claims 6 to 8.

10. A fluid supply subsystem configured to circulate the aforementioned fluid through the balloon. Furthermore, The controller is configured to also control the fluid supply subsystem. The system according to any one of 4 to 9, characterized by the features described herein.

11. The amount of energy absorbed by the tissue surrounding the body cavity segment in which the ultrasonic transducer is located depends in part on the flow rate of the fluid circulating through the balloon. The controller is configured to control the flow rate of the fluid circulating through the balloon to be within a flow rate range of approximately 5 mL / min to approximately 40 mL / min, and particularly approximately 10 mL / min to approximately 15 mL / min. The system according to feature 10.

12. The controller is configured to control the fluid supply subsystem so that the fluid is circulated through the balloon a predetermined time after the first amount of energy is radiated by the ultrasonic transducer. The system according to feature 10 or 11.

13. The predetermined time is within the range of 2 to 12 seconds, and more particularly within the range of 5 to 9 seconds. The system according to feature 12.

14. The specified intermediate diameter separates the lower sub-range from the upper sub-range. The system according to any one of claims 1 to 13.

15. The specified intermediate diameter includes one of approximately 4.5 mm, approximately 5.0 mm, or approximately 5.5 mm. The system according to feature 14.

16. The nominal balloon diameter is selected to be greater than the specified intermediate diameter. A system according to claim 14 or 15, characterized in that it is at least dependent on claim 6.

17. The nominal balloon diameter is selected to be at least 10%, at least 20%, or at least 30% larger than the specified intermediate diameter. The system according to any one of claims 6 to 8.

18. The lower limit of the specified diameter range includes one of approximately 2 mm, approximately 2.5 mm, or approximately 3.0 mm. The upper limit of the specified diameter range includes one of approximately 7.5 mm, approximately 8.0 mm, or approximately 8.5 mm. The system according to any one of features 1 to 17.

19. The acoustic energy of the second quantity is at least 8%, at least 10%, at least 12%, or at least 15% greater than the acoustic energy of the first quantity. The system according to any one of features 1 to 18.

20. The acoustic energy of the first quantity is based on a first acoustic signal having a first acoustic frequency, a first acoustic power, and a first duration. The acoustic energy of the second quantity is based on a second acoustic signal having a second acoustic frequency, a second acoustic power, and a second duration. The second acoustic power is greater than the first acoustic power. The system according to any one of features 1 to 19.

21. The second acoustic power is at least 8%, at least 10%, at least 12%, or at least 15% greater than the first acoustic power. The system according to claim 20, characterized in that it is as described above.

22. The first acoustic frequency is equal to the second acoustic frequency. The system according to claim 20 or 21, characterized in that it is the same as described above.

23. The first duration is equal to the second duration. The system according to any one of 20 to 22, characterized in that it is the same as described above.

24. The first acoustic power and the second acoustic power are either the acoustic patient entry power or the nominal acoustic power set by the controller. The system according to any one of claims 20 to 23, characterized in that it is the same as described above.

25. The total allowable range for generating the first acoustic power and the second acoustic power is less than 15%, less than 11%, or less than 8%. The system according to any one of 20 to 24, characterized by the features described herein.

26. The specified diameter range is at least 4 mm. The system according to any one of claims 1 to 25, characterized by the features described herein.

27. The controller is configured to control the excitation source such that the ultrasonic transducer radiates only the two different amounts of acoustic energy. The system according to any one of features 1 to 26.

28. The acoustic energy of the first quantity is obtained by an acoustic power of approximately 27.5 watts or within a first range of approximately 30.0 watts to approximately 33.0 watts. The acoustic energy of the second quantity is obtained by an acoustic power within the second range of approximately 33.1 watts to approximately 39.0 watts. The system according to any one of features 1 to 27.

29. The acoustic energy of the first quantity is obtained by a first acoustic power of about 29.0 watts or within a first range of about 31.0 watts to about 33.0 watts. The acoustic energy of the second quantity is obtained by a second acoustic power within a second range of approximately 33.1 watts to approximately 38.0 watts. The system according to any one of features 1 to 27.

30. The acoustic energy of the first quantity is obtained by a first acoustic power of about 30.1 watts or about 32.0 watts. The acoustic energy of the second quantity is obtained by a second acoustic power of approximately 36.0 watts. The system according to any one of features 1 to 27.

31. A method for operating a tissue treatment system, The aforementioned tissue treatment system is, A catheter including a distal portion on which an ultrasound transducer is located, An excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, A controller communicatively coupled to the excitation source, Equipped with, The catheter is configured such that at least the distal portion of the catheter can be inserted into a segment of a body cavity having a diameter within a specified diameter range. The diameter range has a lower sub-range and an upper sub-range, The controller is configured to control the excitation source such that the ultrasonic transducer radiates two different amounts of acoustic energy. The two distinct amounts of acoustic energy include a first amount of acoustic energy and a second amount of acoustic energy that is greater than the first amount of acoustic energy. The method involves the following steps performed by the controller, namely, A step of controlling the excitation source by using the ultrasonic transducer, such that when the diameter of the segment of the body cavity to be treated is within the lower sub-range, a first amount of acoustic energy is selectively emitted, and when the diameter of the segment of the body cavity to be treated is within the upper sub-range, a second amount of acoustic energy is selectively emitted. A method characterized by comprising:

32. This is performed by the system described in any one of claims 2 to 30. The method according to feature 31.

33. A catheter including a distal portion on which an ultrasound transducer is located, An excitation source configured to selectively supply energy to the ultrasonic transducer of the catheter, A controller communicatively coupled to the excitation source, Equipped with, The catheter is configured such that at least the distal portion of the catheter can be inserted into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm. The controller is configured to control the excitation source such that the ultrasonic transducer emits only two different amounts of acoustic energy. The two distinct amounts of acoustic energy include a first amount of acoustic energy when the diameter of the segment of the body cavity is within a lower sub-range of the specified diameter range, and a second amount of acoustic energy greater than the first amount of acoustic energy when the diameter of the segment of the body cavity is within an upper sub-range of the specified diameter range. A tissue treatment system characterized by the following features.

34. The specified diameter range, which is at least 4 mm, has a lower limit and an upper limit. The lower limit of the specified diameter range includes one of approximately 2 mm, approximately 2.5 mm, or approximately 3.0 mm. The upper limit of the specified diameter range includes one of approximately 7.5 mm, approximately 8.0 mm, or approximately 8.5 mm. The system according to claim 33, characterized in that way.

35. The specified intermediate diameter separates the lower sub-range of the specified diameter range from the upper sub-range of the specified diameter range. The specified intermediate diameter includes one of approximately 4.5 mm, approximately 5.0 mm, or approximately 5.5 mm. The system according to feature 34.

36. The amount of acoustic energy radiated by the ultrasonic transducer is based on the output power of the excitation source driving the ultrasonic transducer, the frequency of the acoustic signal radiated by the ultrasonic transducer, and the duration of the acoustic signal radiated by the ultrasonic transducer. The controller controls the excitation source, When the diameter of the segment of the body cavity is within the lower sub-range, the excitation source is controlled such that the output power has a first output power level setting for when the diameter of the segment of the body cavity is within the lower sub-range, thereby causing the ultrasonic transducer to radiate a first amount of acoustic energy. When the diameter of the segment of the body cavity is within the upper sub-range, the excitation source is controlled to have a second output power level setting for when the diameter of the segment of the body cavity is within the upper sub-range, which is higher than the first output power level setting, thereby causing the ultrasonic transducer to radiate the second amount of acoustic energy. When the second output power level setting is used to radiate a second amount of acoustic energy, compared to when the first output power level setting is used to radiate a first amount of acoustic energy, the frequency of the acoustic signal radiated by the ultrasonic transducer and the duration of the acoustic signal radiated by the ultrasonic transducer are the same. The system according to any one of claims 1 to 35, characterized by the features described herein.

37. The amount of acoustic energy radiated by the ultrasonic transducer is based on the output power of the excitation source driving the ultrasonic transducer, the frequency of the acoustic signal radiated by the ultrasonic transducer, and the duration of the acoustic signal radiated by the ultrasonic transducer. The controller controls the excitation source, When the diameter of the segment of the body cavity is within the lower sub-range, the ultrasonic transducer is made to emit an acoustic signal for a first duration. When the diameter of the segment of the body cavity is within the upper sub-range, the ultrasonic transducer is made to emit an acoustic signal with a second duration greater than the first duration. When the acoustic signal is radiated for a second duration, compared to when the acoustic signal is radiated for a first duration, the frequency of the acoustic signal radiated by the ultrasonic transducer and the output power of the excitation source driving the ultrasonic transducer are the same. The system according to any one of claims 1 to 35, characterized by the features described herein.

38. The acoustic energy of the first quantity is based on an acoustic power of approximately 27.5 watts or within a first range of approximately 30.0 watts to approximately 33.0 watts. The acoustic energy of the second quantity is based on acoustic power within the second range of approximately 33.1 watts to approximately 39.0 watts. The system according to any one of claims 33 to 37.

39. The acoustic energy of the first quantity is based on a first acoustic power within a first range of approximately 29.0 watts or approximately 31.0 watts to approximately 33.0 watts. The acoustic energy of the second quantity is based on a second acoustic power within a second range of approximately 33.1 watts to approximately 38.0 watts. The system according to any one of claims 33, 38, and 26.

40. The acoustic energy of the first quantity is based on a first acoustic power of approximately 30.1 watts or approximately 32.0 watts. The acoustic energy of the second quantity is based on a second acoustic power of approximately 36.0 watts. The system according to any one of claims 33 to 39.

41. The controller further, Determine the diameter of the segment of the body cavity, Based on the determination that the diameter is within the lower sub-range of the specified diameter range, the excitation source is controlled to cause the ultrasonic transducer to emit the first amount of acoustic energy. Based on the determination that the diameter is within the upper sub-range of the specified diameter range, the excitation source is controlled to cause the ultrasonic transducer to radiate the second amount of acoustic energy. It is structured in this way. The system according to any one of claims 33 to 40.

42. User Interface The system according to any one of claims 33 to 41, further comprising the above.

43. The user interface is configured to allow the user to specify whether the diameter of the segment of the body cavity is within the lower sub-range of the specified diameter range or within the upper sub-range of the specified diameter range. The system according to feature 42.

44. The controller is configured to automatically provide the diameter of the segment of the body cavity, The user interface is further configured to display a warning message when the diameter of the automatically provided segment of the body cavity is not within the sub-range entered by the user. The system according to feature 43.

45. The user interface is configured to allow the user to specify the type of body cavity. The controller is configured to select whether the body cavity is within the lower sub-range of the specified diameter range or within the upper sub-range of the specified diameter range, based on the type of body cavity specified by the user using the user interface. The system according to any one of claims 33 to 44.

46. The controller accesses information stored in memory regarding multiple different types of body cavities, and whether each type of body cavity is within the lower sub-range of the specified diameter range or within the upper sub-range of the specified diameter range. The system according to claim 45, characterized in that it is the same as described in the previous version.

47. The aforementioned multiple different types of body cavities include at least the main renal artery, the adrenal artery, and the renal artery branches. The system described in claim 46.

48. The controller further, When the diameter of the segment of the body cavity is specified to be within the lower sub-range using the user interface, the excitation source is controlled such that the ultrasonic transducer selectively emits the first amount of acoustic energy. When the diameter of the body cavity segment is specified to be within the upper sub-range using the user interface, the excitation source is controlled such that the ultrasonic transducer selectively emits the second amount of acoustic energy. It is configured in such a way The system according to any one of features 41 to 47.

49. The user interface is further configured to display a warning message when the automatically determined estimated diameter of the body cavity segment is outside the sub-range entered by the user. The system according to any one of features 41 to 48.

50. The distal portion of the catheter further comprises a centering mechanism configured to approximately center the ultrasonic transducer within the body cavity. The system according to any one of claims 33 to 49.

51. The distal portion of the catheter further includes a balloon in which the ultrasonic transducer is located. The balloon is configured to roughly center the ultrasonic transducer within the body cavity and to circulate fluid through the balloon to cool at least a portion of the tissue adjacent to the body cavity in which the ultrasonic transducer is positioned. The system according to any one of claims 33 to 50, characterized in that way.

52. A fluid supply subsystem configured to circulate the aforementioned fluid through the balloon. Furthermore, The controller is configured to also control the fluid supply subsystem, The amount of energy absorbed by the tissue surrounding the body cavity segment in which the ultrasonic transducer is located depends in part on the flow rate of the fluid circulating through the balloon. The system according to claim 51, characterized in that it is the same as described above.

53. The flow rate of the fluid circulating through the balloon is within the range of approximately 5 mL / min to approximately 40 mL / min. The system according to claim 52, characterized in that it is the same as described above.

54. The flow rate of the fluid circulating through the balloon is approximately 10 mL / min to approximately 15 mL / min. The system according to claim 53, characterized in that it is as described above.

55. The balloon includes a compliant balloon. The system according to any one of 51 to 54, characterized by the features described herein.

56. The compliant balloon is configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, the compliant balloon includes one or more folds. The system according to claim 55, characterized in that it is the same as described above.

57. The one or more folds include at least one of the following: a wrinkle, one or more spiral folds, or one or more longitudinal folds. The system according to claim 56, characterized in that it is as follows.

58. The one or more folds in the compliant balloon that exist when the compliant balloon is partially inflated such that its diameter is smaller than its nominal balloon diameter at least partially attenuate a portion of the acoustic energy radiated by the ultrasonic transducer, thereby reducing the amount of acoustic energy passing through the compliant balloon when the body cavity adjacent to the compliant balloon has a diameter within a smaller diameter subset of the specified diameter range, compared to when the compliant balloon is inflated to have a diameter at least the nominal balloon diameter of the compliant balloon and the diameter of the segment of the body cavity adjacent to the compliant balloon is within a larger diameter subset of the specified diameter range. The system according to claim 56 or 57, characterized in that it is the system according to claim 56 or 57.

59. The compliant balloon has a nominal balloon diameter and a corresponding nominal balloon wall thickness. When the compliant balloon is inflated beyond the nominal balloon diameter, the compliant balloon stretches, and the balloon wall thickness becomes thinner than the nominal balloon wall thickness. As a result, when the diameter of the body cavity adjacent to the compliant balloon falls within a larger diameter subset of the specified diameter range, the attenuation of acoustic energy emitted by the ultrasonic transducer is less compared to when the diameter of the segment of the body cavity adjacent to the compliant balloon falls within a smaller diameter subset of the specified diameter range. The system according to any one of 56 to 58, characterized in that it is the system described above.

60. The compliant balloon is made from at least one of the following materials: nylon, polyether block amide, or thermoplastic polyurethane. The system according to any one of 55 to 59, characterized by the features described herein.

61. The body cavity includes the renal artery. The system according to any one of claims 33 to 60.

62. The body cavity includes one of the following: veins, pulmonary arteries, vascular cavities, celiac arteries, common hepatic arteries, proper hepatic arteries, gastroduodenal arteries, hepatic arteries, splenic arteries, gastric arteries, blood vessels, non-vascular cavities, airways, sinuses, esophagus, respiratory cavities, digestive cavities, stomach, duodenum, jejunum, or cancerous tissue. The system according to any one of claims 33 to 60.

63. The system is configured to generate one or more injuries in the tissue surrounding the body cavity in which the ultrasonic transducer is positioned, and the depth of the one or more injuries is configured to be within a range of approximately 2 mm to approximately 10 mm. The system according to any one of features 1 to 62.

64. The depth of the damage is approximately 6 mm. The system according to claim 63.

65. A tissue treatment method using the tissue treatment system described in any one of claims 1 to 64, The steps include inserting the distal portion of the catheter into a segment of a body cavity having a diameter within the specified diameter range of at least 4 mm, The process involves using the excitation source to provide energy to the ultrasonic transducer of the catheter, and when the diameter of the segment of the body cavity is within the specified diameter range of at least 4 mm, the ultrasonic transducer radiates approximately the same amount of acoustic energy. A method characterized by comprising:

66. A tissue treatment method using the tissue treatment system described in any one of claims 1 to 64, The steps include inserting the distal portion of the catheter into a segment of a body cavity having a diameter within the specified diameter range of at least 4 mm, A step of receiving input regarding whether the diameter of the segment of the body cavity is within the lower sub-range of the specified diameter range or within the upper sub-range of the specified diameter range, The steps include: causing the excitation source to provide energy to the ultrasonic transducer of the catheter, and causing the ultrasonic transducer to emit the first amount of acoustic energy when the diameter of the segment of the body cavity is within the lower sub-range of the specified diameter range; The steps include: causing the excitation source to provide energy to the ultrasonic transducer of the catheter, and causing the ultrasonic transducer to emit the second amount of acoustic energy when the diameter of the segment of the body cavity is within the upper sub-range of the specified diameter range; A method characterized by comprising:

67. A method of using a tissue treatment system comprising a catheter including a distal portion on which an ultrasound transducer is located, The steps include inserting the distal portion of the catheter into a segment of a body cavity having a diameter within the specified diameter range of at least 4 mm, so that the ultrasonic transducer is positioned within the segment of the body cavity having a diameter within the specified diameter range of at least 4 mm, The steps include: when the diameter of the segment of the body cavity is within the specified diameter range of at least 4 mm, the ultrasonic transducer is made to emit approximately the same amount of acoustic energy; A method characterized by comprising:

68. The distal portion of the catheter further includes a compliant balloon in which the ultrasonic transducer is disposed. The compliant balloon is configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, the compliant balloon includes one or more folds. This method further, The steps include: inflating the compliant balloon so that the compliant balloon is adjacent to the cavity wall of the body cavity segment in which the ultrasonic transducer is located; A step of using the one or more folds of the compliant balloon to at least partially attenuate a portion of the acoustic energy radiated by the ultrasonic transducer, thereby reducing the amount of acoustic energy passing through the compliant balloon when the diameter of the segment of the body cavity adjacent to the compliant balloon is within a smaller diameter subset of the specified diameter range, compared to when the compliant balloon is inflated to at least the nominal balloon diameter of the compliant balloon and the diameter of the segment of the body cavity adjacent to the compliant balloon is within a larger diameter subset of the specified diameter range, The method according to 67, characterized by comprising:

69. The body cavity includes the renal artery. The method according to 67 or 68, characterized by the features described above.

70. The body cavity includes one of the following: veins, pulmonary arteries, vascular cavities, celiac arteries, common hepatic arteries, proper hepatic arteries, gastroduodenal arteries, hepatic arteries, splenic arteries, gastric arteries, blood vessels, non-vascular cavities, airways, sinuses, esophagus, respiratory cavities, digestive cavities, stomach, duodenum, jejunum, or cancerous tissue. The method according to 67 or 68, characterized by the features described above.

71. A method of using a tissue treatment system comprising a catheter including a distal portion on which an ultrasound transducer is located, The steps include inserting the distal portion of the catheter into a segment of a body cavity having a diameter within a specified diameter range of at least 4 mm, so that the ultrasonic transducer is positioned within the segment of the body cavity having a diameter within the specified diameter range of at least 4 mm, A controller associated with the ultrasonic transducer includes the step of receiving input as to whether the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within a lower sub-range of the specified diameter range or within an upper sub-range of the specified diameter range, Upon receiving input that the diameter of the segment of the body cavity is within the lower sub-range of the specified diameter range, the ultrasonic transducer is made to emit a first amount of acoustic energy. Upon receiving input indicating that the diameter of the segment of the body cavity is within the upper sub-range of the specified diameter range, the ultrasonic transducer is made to emit a second amount of acoustic energy greater than the first amount of acoustic energy. A method characterized by comprising:

72. During the process of receiving the aforementioned input, the input is received from the user via a user interface. The method according to feature 71.

73. The process of receiving the aforementioned input is as follows: The process of receiving instructions from the user via a user interface connected to the controller, indicating which of several different types of body cavities the ultrasonic transducer is located in, A step of automatically classifying, based on the instructions received via the user interface, whether the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within the lower sub-range of the specified diameter range or within the upper sub-range of the specified diameter range, The method according to 72, characterized by including the following:

74. The aforementioned multiple different types of body cavities include at least the main renal artery, the adrenal artery, and the renal artery branches. The method according to feature 73.

75. During the process of receiving the aforementioned input, the input is received from the controller. The controller is configured to automatically determine whether the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within the lower sub-range of the specified diameter range or within the upper sub-range of the specified diameter range. The method according to feature 71.

76. The distal portion of the catheter further includes a compliant balloon in which the ultrasonic transducer is disposed. The compliant balloon is configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, the compliant balloon includes one or more folds. This method further, The steps include: inflating the compliant balloon so that the compliant balloon is adjacent to the cavity wall of the body cavity segment in which the ultrasonic transducer is located; A step of using the one or more folds of the compliant balloon to at least partially attenuate a portion of the acoustic energy radiated by the ultrasonic transducer, thereby reducing the amount of acoustic energy passing through the compliant balloon when the diameter of the segment of the body cavity adjacent to the compliant balloon is within a smaller diameter subset of the specified diameter range, compared to when the compliant balloon is inflated to at least the nominal balloon diameter of the compliant balloon and the diameter of the segment of the body cavity adjacent to the compliant balloon is within a larger diameter subset of the specified diameter range, The method according to 67, characterized by comprising:

77. The body cavity includes the renal artery. The method according to any one of 71 to 76, characterized by...

78. The body cavity includes one of the following: veins, pulmonary arteries, vascular cavities, celiac arteries, common hepatic arteries, proper hepatic arteries, gastroduodenal arteries, hepatic arteries, splenic arteries, gastric arteries, blood vessels, non-vascular cavities, airways, sinuses, esophagus, respiratory cavities, digestive cavities, stomach, duodenum, jejunum, or cancerous tissue. The method according to 71 or 76, characterized by the features described herein.

79. A catheter comprising a distal portion configured to deliver neuromodulatory energy to a segment of a body cavity, An excitation source configured to selectively provide nerve-modulating energy to the catheter, A controller communicatively coupled to the excitation source, Equipped with, The controller is configured to control the excitation source such that when the diameter of the segment of the body cavity is within a first specified diameter range of at least 4 mm, the catheter emits approximately the same amount of neuromodulatory energy. A tissue treatment system characterized by the following features.

80. The first specified diameter range is at least 5 mm. The system according to feature 79.

81. The controller is further configured to control the excitation source such that when the diameter of the segment of the body cavity is within a second specified diameter range of at least 1 mm, the catheter emits a different amount of neuromodulatory energy. The system according to feature 79.

82. The first specified diameter range, which is at least 4 mm, includes an upper limit of the first specified diameter range, the upper limit of the first specified diameter range includes one of approximately 7.5 mm, approximately 8.0 mm, or approximately 8.5 mm. The second specified diameter range, which is at least 1 mm, includes a lower limit of the second specified diameter range, which includes one of approximately 2 mm, approximately 2.5 mm, or approximately 3.0 mm. The system according to feature 81.

83. The first specified diameter range, which is at least 4 mm, includes diameters between approximately 4.1 mm and approximately 8.0 mm. The second specified diameter range, which is at least 1 mm, includes diameters between approximately 3.0 mm and approximately 4.0 mm. The system according to feature 81.

84. The first specified diameter range, which is at least 4 mm, includes diameters between approximately 4.1 mm and approximately 8.0 mm. The second specified diameter range, which is at least 1 mm, includes diameters between approximately 2.0 mm and approximately 4.0 mm. The system according to feature 81.

85. The distal portion configured to deliver neuromodulatory energy to a segment of the body cavity includes an ultrasonic transducer. The amount of acoustic energy radiated by the ultrasonic transducer is based on the output power of the excitation source driving the ultrasonic transducer, the frequency of the acoustic signal radiated by the ultrasonic transducer, and the duration of the acoustic signal radiated by the ultrasonic transducer. The controller is configured to control the excitation source such that, when the diameter of the segment of the body cavity is within a first specified diameter range of at least 4 mm, the output power is approximately the same, the frequency of the acoustic signal emitted by the ultrasonic transducer is approximately the same, and the duration of the acoustic signal emitted by the ultrasonic transducer is approximately the same, thereby causing the ultrasonic transducer to emit approximately the same amount of acoustic energy when the diameter of the segment of the body cavity is within a first specified diameter range of at least 4 mm. The system according to any one of 79 to 84, characterized by...

86. The distal portion of the catheter further includes a balloon in which the ultrasonic transducer is located. The balloon is configured to roughly center the ultrasonic transducer within the body cavity and to circulate fluid through the balloon to cool at least a portion of the tissue adjacent to the body cavity in which the ultrasonic transducer is positioned. The system according to claim 85, characterized in that it is as follows.

87. A fluid supply subsystem configured to circulate the aforementioned fluid through the balloon. Furthermore, The controller is configured to also control the fluid supply subsystem, The amount of energy absorbed by the tissue surrounding the body cavity segment in which the ultrasonic transducer is located depends in part on the flow rate of the fluid circulating through the balloon. The controller is configured to control the fluid supply subsystem such that the flow rate of the fluid circulating through the balloon is approximately the same when the diameter of the segment of the body cavity is within the specified diameter range, which is at least 4 mm. The system according to claim 86.

88. The flow rate of the fluid circulating through the balloon is within the range of approximately 10 mL / min to approximately 15 mL / min. The system according to feature 87.

89. The balloon is a compliant balloon. The system according to any one of the features of 86 to 88.

90. The balloon is a compliant balloon containing thermoplastic polyurethane. The system according to any one of the features of 86 to 88.

91. The balloon is a compliant balloon containing pelletan having a Shore D durometer hardness of 55. The system according to any one of the features of 86 to 88.

92. The balloon is a compliant balloon configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, the compliant balloon includes one or more folds. The system according to any one of the features of 86 to 88.

93. The one or more folds include at least one of the following: a wrinkle, one or more spiral folds, or one or more longitudinal folds. The system according to feature 92.

94. The one or more folds in the compliant balloon that exist when the compliant balloon is partially inflated such that the diameter of the compliant balloon is smaller than the nominal balloon diameter of the compliant balloon at least partially attenuate a portion of the acoustic energy radiated by the ultrasonic transducer, thereby reducing the amount of acoustic energy passing through the compliant balloon when the body cavity adjacent to the compliant balloon has a diameter within the lower diameter subset of the specified diameter range, compared to when the compliant balloon is inflated to have a diameter of at least the nominal balloon diameter of the compliant balloon and the diameter of the segment of the body cavity adjacent to the compliant balloon is within the upper diameter subset of the specified diameter range. The system according to claim 92 or 93, characterized in that it is the system according to claim 93.

95. The compliant balloon has a nominal balloon diameter and a corresponding nominal balloon wall thickness. When the compliant balloon is inflated beyond the nominal balloon diameter, the compliant balloon stretches, and the balloon wall thickness becomes thinner than the nominal balloon wall thickness. As a result, when the diameter of the body cavity adjacent to the compliant balloon is greater than the nominal balloon diameter, the attenuation of acoustic energy emitted by the ultrasonic transducer is less compared to when the diameter of the segment of the body cavity adjacent to the compliant balloon is smaller than the nominal balloon diameter. The system according to any one of 89 to 94, characterized by...

96. The approximately same amount of acoustic energy radiated by the ultrasonic transducer when the diameter of the segment of the body cavity is within the first specified diameter range is based on an acoustic power of approximately 27.5 watts or approximately 30.0 watts to approximately 39.0 watts. The system according to any one of 79 to 95, characterized by the features described herein.

97. The approximately same amount of acoustic energy radiated by the ultrasonic transducer when the diameter of the segment of the body cavity is within the first specified diameter range is based on an acoustic power of approximately 29.0 watts or approximately 32.0 watts to approximately 36.0 watts. The system according to any one of 79 to 95, characterized by the features described herein.

98. The approximately same amount of acoustic energy radiated by the ultrasonic transducer when the diameter of the segment of the body cavity is within the first specified diameter range is based on an acoustic power in the range of approximately 33.0 watts to approximately 34.0 watts. The system according to any one of 79 to 95, characterized by the features described herein.

99. The body cavity includes the renal artery. The system according to any one of 79 to 98, characterized by the above.

100. The aforementioned body cavity includes the pulmonary artery. The system according to any one of 79 to 98, characterized by the above.

101. The acoustic energy is selected to generate lesions having a depth within a range of approximately 2.5 mm to 8 mm. The system according to any one of claims 79 to 100, characterized by the features described herein.

102. The acoustic energy is selected to generate lesions having a depth within a range of approximately 5.5 mm to 7.5 mm. The system according to any one of claims 79 to 100, characterized by the features described herein.

103. The acoustic energy is selected to generate lesions having a depth within a range of approximately 5.5 mm to 6.5 mm. The system according to any one of claims 79 to 100, characterized by the features described herein.

104. The acoustic energy is selected to generate lesions having a depth within a range of approximately 5.5 mm to 6.0 mm. The system according to any one of claims 79 to 100, characterized by the features described herein.

105. The one or more folds of the compliant balloon present when the compliant balloon is partially inflated such that the diameter of the compliant balloon is smaller than the nominal balloon diameter of the compliant balloon are configured to attenuate more of the acoustic energy radiated by the ultrasonic transducer, thereby allowing less acoustic energy to pass through the compliant balloon when the compliant balloon is adjacent to a cavity segment having a diameter within a smaller diameter subset of the specified diameter range compared to when the compliant balloon is adjacent to a cavity segment having a diameter within a larger diameter subset of the specified diameter range. The system according to claim 56 or 57, characterized in that it is the system according to claim 56 or 57.

106. The distal portion of the catheter further includes a compliant balloon in which the ultrasonic transducer is disposed. The compliant balloon is configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, the compliant balloon includes one or more folds. This method further, The steps include: inflating the compliant balloon so that the compliant balloon is adjacent to the cavity wall of the body cavity segment in which the ultrasonic transducer is located; The steps include utilizing the one or more folds of the compliant balloon to attenuate more of the acoustic energy radiated by the ultrasonic transducer, thereby allowing less acoustic energy to pass through the compliant balloon when the compliant balloon is adjacent to a body cavity segment having a diameter within a smaller diameter subset of the specified diameter range compared to when the compliant balloon is adjacent to a body cavity segment having a diameter within a larger diameter subset of the specified diameter range, The method according to 71, characterized by being provided with

107. The distal portion of the catheter further includes a compliant balloon in which the ultrasonic transducer is disposed. The compliant balloon is configured such that when it is partially inflated to a diameter smaller than the nominal balloon diameter of the compliant balloon, the compliant balloon includes one or more folds. This method further, When the diameter of the segment of the body cavity in which the ultrasonic transducer is placed is within the lower sub-range of the specified diameter range, the ultrasonic transducer radiates a first amount of acoustic energy, while the one or more folds of the compliant balloon are used to attenuate more of the acoustic energy radiated by the ultrasonic transducer, thereby allowing less acoustic energy to pass through the compliant balloon when the compliant balloon is adjacent to a segment of the body cavity having a diameter within a smaller diameter subset of the lower sub-range of the specified diameter range, compared to when the compliant balloon is adjacent to a segment of the body cavity having a diameter within a larger diameter subset of the lower sub-range of the specified diameter range. When the diameter of the segment of the body cavity in which the ultrasonic transducer is located is within the upper sub-range of the specified diameter range, the ultrasonic transducer radiates a second amount of acoustic energy greater than the first amount of acoustic energy, while utilizing the one or more folds of the compliant balloon to attenuate more of the acoustic energy radiated by the ultrasonic transducer, thereby allowing less acoustic energy to pass through the compliant balloon when the compliant balloon is adjacent to a segment of the body cavity having a diameter within a smaller diameter subset of the upper sub-range of the specified diameter range compared to when the compliant balloon is adjacent to a segment of the body cavity having a diameter within a larger diameter subset of the upper sub-range of the specified diameter range. The method according to 71, characterized by being provided with

108. The one or more folds of the compliant balloon present when the compliant balloon is partially inflated such that the diameter of the compliant balloon is smaller than the nominal balloon diameter of the compliant balloon are configured to attenuate more of the acoustic energy radiated by the ultrasonic transducer, thereby allowing less acoustic energy to pass through the compliant balloon when the compliant balloon is adjacent to a cavity segment having a diameter within a smaller diameter subset of the specified diameter range compared to when the compliant balloon is adjacent to a cavity segment having a diameter within a larger diameter subset of the specified diameter range. The system according to claim 92 or 93, characterized in that it is the system according to claim 93.

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