Medical device equipped with acoustic sensor, and method for locating the medical device and sound source.

Abstract

The catheter includes a shaft, a tip located at the distal end of the shaft, and at least one acoustic sensor located on or within the shaft, each acoustic sensor located at a distance from the distal end of the shaft, and at least one electrical conductor located on or within the shaft, each electrical conductor electrically connecting each acoustic sensor to one or more electrical connection points in a housing attached to the proximal end of the shaft. The catheter and the acoustic source are localized to each other using acoustic signals transmitted between the acoustic source and the catheter. [Solution]

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Provisional Application No. 63 / 498,297, entitled "Positioning System and Method for a Therapeutic Device for a Catheter," filed on April 26, 2023, the content of which is incorporated herein by reference.

[0002] This application generally relates to a medical device having one or more acoustic sensors and to locating an acoustic source and such a medical device relative to each other.

Background Art

[0003] Many therapeutic procedures require positioning and monitoring the position of an intravascular catheter. Although it is possible to visualize the catheter by X - ray imaging, alternative methods that do not use ionizing radiation are preferred. Although an ultrasonic scanner can provide non - ionizing visualization, image resolution can be an issue, and as a result, it may be difficult to reliably identify and monitor the position of the catheter. For example, image resolution improves with higher frequencies, but high frequencies have a shallow penetration depth, making ultrasonic imaging difficult at deeper locations. It is desirable to improve the ability to identify and monitor the position of the catheter without using ionizing radiation.

[0004] In many therapeutic procedures, it is desirable to use the position of the catheter as a marker, for example, for the delivery of electromagnetic energy or acoustic energy to a specific region of the human body. The delivery of acoustic energy to a target usually involves various challenges. One challenge is the alignment of the ultrasonic beam to the target, which is also affected by the diffraction and deflection of acoustic waves passing through different tissue layers along the acoustic path to the target. Another challenge is the acoustic coupling between the acoustic source and the patient's skin and ensuring an acoustic window within the patient's body for efficiently transmitting the acoustic wave to the target.

Summary of the Invention

Means for Solving the Problems

[0005] While the exemplary embodiments described herein possess novel features, none of them are essential, nor do any single feature alone represent a desirable characteristic. The following description and drawings detail specific exemplary embodiments of the disclosure, illustrating several exemplary means by which various principles of the disclosure can be implemented. However, such exemplary examples do not encompass all possible embodiments of the disclosure. Without limiting the scope of the claims, some of the advantageous features are summarized below. Other objectives, advantages, and novel features of the disclosure are revealed in the following detailed description, which is considered in conjunction with the drawings. They are intended to illustrate the invention and are not intended to limit it.

[0006] One aspect of the present invention relates to a catheter comprising: a shaft; a tip portion located at the distal end of the shaft; at least one acoustic sensor located on or within the shaft, each acoustic sensor located at a distance from the distal end of the shaft; and at least one electrical conductor located on or within the shaft, each electrical conductor electrically connecting each acoustic sensor to one or more electrical connection points in a housing attached to the proximal end of the shaft.

[0007] In one or more embodiments, each acoustic sensor has a piezoelectric polymer film arranged around at least a portion of the circumference of the shaft. In one or more embodiments, the piezoelectric polymer film has polyvinylidene fluoride.

[0008] In one or more embodiments, the shaft includes an inner tube and an outer tube, each of the piezoelectric polymer films is arranged around at least a portion of the circumference of the inner tube, and the at least one electrical conductor is arranged between the inner tube and the outer tube. In one or more embodiments, the inner tube is defined by a wall, the wall having an inner wall thickness, and one or more regions of the wall having a thickness increased compared to the inner wall thickness. In one or more embodiments, the outer tube is defined by a wall, the wall having an outer wall thickness, and one or more regions of the wall having a thickness increased compared to the outer wall thickness. In one or more embodiments, a spacer is arranged between the inner tube and the outer tube.

[0009] In one or more embodiments, the one or more electrical connection points are electrically coupled to a cable extending through the housing. In one or more embodiments, the one or more electrical connection points are formed on a printed circuit board located within the housing. In one or more embodiments, the catheter further has a wireless communication circuit electrically coupled to the one or more electrical connection points.

[0010] In one or more embodiments, the housing includes a port having a hole aligned with the central channel of the shaft. In one or more embodiments, the at least one acoustic sensor includes a first acoustic sensor and a second acoustic sensor, the first sensor and the second sensor being separated by a predetermined distance.

[0011] Another aspect of the present invention is a method for locating an acoustic source and a medical device relative to each other, comprising: a. introducing the medical device into a mammal; b. acoustically coupling the acoustic source to the mammal at a position corresponding to a target position of the medical device, wherein the acoustic source comprises a housing and an acoustic source transducer disposed within the housing; c. generating an acoustic signal using the acoustic source transducer; d. receiving the acoustic signal using an acoustic sensor on or within the medical device, wherein the acoustic sensor communicates electrically or wirelessly with a detector; e. determining the time of flight (ToF) of the acoustic signal transmitted between the acoustic source transducer and the acoustic sensor using the detector; f. determining the distance between the acoustic source transducer and the acoustic sensor using the detector and the ToF; and g. locating the acoustic source and the medical device in real time, at least partially based on the distance between the acoustic source transducer and the acoustic sensor using the detector.

[0012] In one or more embodiments, the acoustic sensor is a first acoustic sensor, the medical device includes at least a second acoustic sensor, and the method further comprises the steps of: receiving the acoustic signal with the first and second acoustic sensors; determining a first ToF of the acoustic signal transmitted between the acoustic source transducer and the first acoustic sensor using the detector; determining a second ToF of the acoustic signal transmitted between the acoustic source transducer and the second acoustic sensor using the detector; determining a first distance between the acoustic source transducer and the first acoustic sensor using the first ToF using the detector; determining a second distance between the acoustic source transducer and the second acoustic sensor using the second ToF using the detector; and locating the acoustic source and the medical device relative to each other, at least partially based on the first and second distances.

[0013] In one or more embodiments, the medical device includes a plurality of acoustic sensors, and the acoustic source includes a plurality of acoustic source transducers, the method further comprising the steps of: sequentially generating the acoustic signal with at least a first acoustic source transducer and a second acoustic source transducer among the plurality of acoustic source transducers; receiving the acoustic signal with each acoustic sensor; determining the ToF of each of the acoustic signals transmitted between (a) each of the at least first acoustic source transducer and the second acoustic source transducer and (b) each acoustic sensor; determining the respective distances between (a) each of the at least first acoustic source transducer and the second acoustic source transducer and (b) each acoustic sensor using the respective ToFs; and at least partially locating the acoustic source and the medical device relative to each other based on the respective distances.

[0014] In one or more embodiments, the position is a first position, and the method further comprises the step of performing at least steps b to f while the sound source is located in the first position, then moving the sound source to a second position, and repeating steps b to f while the sound source is located in the second position, thereby improving the resolution of the relative positioning of the sound source and the medical device compared to when the positioning is performed while the sound source is located only in the first position.

[0015] In one or more embodiments, the medical device has a catheter which is introduced into an organ, and the method further comprises the steps of introducing an acoustic enhancer proximal to the calcification by the catheter, applying acoustic energy by an acoustic source, and generating cavitation with the acoustic energy and the acoustic enhancer to decompose at least a portion of the calcification.

[0016] In one or more embodiments, the method further comprises the step of adjusting the position of the sound source in accordance with the relative positioning of the sound source and the medical device by a robotic positioner communicating with the detector. In one or more embodiments, the method further comprises the step of displaying the relative positions of the sound source and the medical device on the detector or on a display screen that electrically communicates with the detector.

[0017] In one or more embodiments, the medical device has a catheter or a guidewire.

[0018] Another aspect of the present invention is a method for locating an acoustic source and a catheter relative to each other, the method comprising: a. introducing the catheter into a mammal, the catheter comprising a shaft and a tip portion located at the distal end of the shaft, and at least one acoustic sensor located on or within the shaft, each acoustic sensor located at a respective distance from the distal end of the shaft; b. acoustically coupling the acoustic source to the mammal at a position corresponding to the target position of the catheter, the acoustic source comprising a housing and a plurality of acoustic source transducers located within the housing; c. generating a broad acoustic energy beam with the acoustic source; and d. determining a measurement distance between the acoustic source transducer and the at least one acoustic sensor using a detector that electrically or wirelessly communicates with the at least one acoustic sensor, wherein the measurement distance is determined by the acoustic source The steps include: a determining step, which is at least in part based on the time of flight (ToF) of the acoustic signal transmitted between the transducer and each acoustic sensor; e. setting the focal length of the acoustic source transducer corresponding to the measurement distance; f. generating a focused beam of acoustic energy by the acoustic source while moving the acoustic source parallel to a first axis perpendicular to the acoustic axis of the acoustic transducer, wherein the focused beam is focused to the focal length; g. monitoring the output signals of at least one acoustic sensor with the detector to determine a first maximum amplitude signal while the focused beam is being generated, wherein the first maximum amplitude represents a first position determination with respect to the first axis; h. sweeping the focused beam with respect to a second axis perpendicular to the acoustic axis of the acoustic transducer, after step g, wherein the ultrasonic source is positioned at a position corresponding to the first maximum amplitude signal; and i.The present invention relates to a method comprising: j. monitoring the output signal of at least one acoustic sensor with the detector to determine a second maximum amplitude signal while the focused beam is being swept, wherein the second maximum amplitude represents a second position determination with respect to the second axis; j. rotating the focused beam with respect to the acoustic axis after step h; and k. monitoring the output signal of at least one acoustic sensor with the detector to determine a third maximum amplitude signal while the focused beam is being rotated, wherein the third maximum amplitude represents a third position determination with respect to the acoustic axis.

[0019] In one or more embodiments, the method further comprises the step of locking the sound source to a position corresponding to the first maximum amplitude signal.

[0020] Another aspect of the present invention relates to a guide wire comprising: a core; a coil coaxially arranged on the core; a protective coating disposed on the coil; at least one acoustic sensor disposed at respective distances from the distal end of the shaft; and at least one electrical conductor disposed within the protective coating, each electrical conductor electrically connecting each acoustic sensor to one or more electrical connection points in a housing attached to the proximal end of the guide wire.

[0021] In one or more embodiments, each acoustic sensor has a piezoelectric polymer film disposed around at least a portion of the circumference of the core. In one or more embodiments, each acoustic sensor has a piezoelectric polymer film disposed around at least a portion of the circumference of the protective film. In one or more embodiments, each acoustic sensor has a piezoelectric polymer film disposed on the protective film. [Brief explanation of the drawing]

[0022] For a full understanding of the nature and advantages of the concepts disclosed herein, reference is made to the detailed description of the preferred embodiments and the accompanying drawings. [Figure 1] FIG. 1 is a block diagram of a system for acoustically localizing an acoustic source with respect to a catheter, according to one embodiment. [Figure 2] FIG. 2 is an isometric view of the catheter shown in FIG. 1, according to one embodiment. [Figure 3] FIG. 3 is an enlarged view of the distal end of the catheter shown in FIG. 2. [Figure 4A] FIGS. 4A - C are cross-sectional views of a shaft of a catheter in a first plane, according to different embodiments. [Figure 4B] FIGS. 4A - C are cross-sectional views of a shaft of a catheter in a first plane, according to different embodiments. [Figure 4C] FIGS. 4A - C are cross-sectional views of a shaft of a catheter in a first plane, according to different embodiments. [Figure 5] FIG. 5 is a cross-sectional view of a shaft of a catheter in a second plane, according to one embodiment. [Figure 6A] FIGS. 6A - D are cross-sectional views of a shaft of a catheter in a third plane, according to different embodiments. [Figure 6B] FIGS. 6A - D are cross-sectional views of a shaft of a catheter in a third plane, according to different embodiments. [Figure 6C] FIGS. 6A - D are cross-sectional views of a shaft of a catheter in a third plane, according to different embodiments. [Figure 6D] FIGS. 6A - D are cross-sectional views of a shaft of a catheter in a third plane, according to different embodiments. [Figure 7] FIG. 7 is a top view of the housing of the catheter shown in FIG. 2 with the cover removed. [Figure 8] FIG. 8 is a flowchart of a method for localizing an acoustic source and a catheter relative to each other. [Figure 9]Figure 9 shows an exemplary location identification method according to one embodiment. [Figure 10] Figure 10 shows an exemplary location identification method according to another embodiment. [Figure 11] Figure 11 is a flowchart of a method for locating an acoustic source and a catheter relative to each other according to another embodiment. [Figure 12] Figure 12 shows an exemplary coordinate system. [Figure 13A] Figures 13A and 13B show exemplary traces of two acoustic sensors on a catheter and their respective differential signals. [Figure 13B] Figures 13A and 13B show exemplary traces of two acoustic sensors on a catheter and their respective differential signals. [Figure 14] Figure 14 shows exemplary traces from two acoustic sensors on a catheter oriented along the acoustic axis of the acoustic source. [Figure 15] Figure 15 is a block diagram of a system for acoustically locating an acoustic source relative to a catheter, according to another embodiment. [Figure 16] Figure 16 is a partially transparent side view of a guide wire according to one embodiment. [Figure 17A] Figures 17A and 17B are cross-sectional views of the guide wire shown in Figure 16 according to different embodiments. [Figure 17B] Figures 17A and 17B are cross-sectional views of the guide wire shown in Figure 16 according to different embodiments. [Figure 18] Figure 18 is a partially transparent side view of a guide wire according to another embodiment. [Figure 19A] Figures 19A-C are cross-sectional views of the guide wire shown in Figure 18 according to different embodiments. [Figure 19B] Figures 19A-C are cross-sectional views of the guide wire shown in Figure 18 according to different embodiments. [Figure 19C] Figures 19A-C are cross-sectional views of the guide wire shown in Figure 18 according to different embodiments. [Figure 20]Figure 20 is a block diagram of a system for acoustically locating an acoustic source relative to a guide wire according to one embodiment. [Figure 21] Figure 21 shows an exemplary embodiment in which a medical device equipped with multiple acoustic sensors is inserted into the aggregate system of a human kidney through the ureter. [Modes for carrying out the invention]

[0023] The catheter includes a shaft equipped with one or more acoustic sensors, which are located on or within the shaft at respective distances from the distal end of the shaft. Each acoustic sensor may include a piezoelectric polymer film, which is arranged around part or all of the circumference of the inner or outer tube of the shaft. The outer tube is located on the inner tube and covers the acoustic sensors. Lead wires and wires for the acoustic sensors may be arranged between the inner and outer tubes.

[0024] The guidewire comprises a coil, a core, and one or more acoustic sensors, the one or more acoustic sensors being positioned on or within the guidewire at respective distances from the distal end of the guidewire. Each acoustic sensor may include a piezoelectric polymer film, each piezoelectric polymer film being positioned around part or all of the circumference of the protective coating of the coil, or around part or all of the circumference of the core.

[0025] Acoustic sensors can be used to locate a catheter or guidewire and an acoustic source relative to each other without imaging after the catheter or guidewire has been inserted or introduced into a mammal.

[0026] Figure 1 is a block diagram of a system 10 for acoustically locating an acoustic source 12 relative to a catheter 14 according to one embodiment. The acoustic source 12 includes a housing 16 and one or more acoustic transducers 18 disposed within the housing 16. The acoustic source 12 may have an acoustic therapy head configured to generate acoustic energy for therapeutic or medical procedures. The acoustic source 12 may be placed on the skin 20 of a mammal 22 such as a human. For example, an acoustic transmission medium 24 such as water, a water cushion, an acoustically coupled oil, and / or an acoustically coupled gel may be placed between the acoustic source 12 and the skin 20 (e.g., in direct physical contact) to improve acoustic transmission. The acoustic source 12 may be powered by a power supply, an amplifier, and / or a controller 25 electrically connected to the acoustic source 12.

[0027] The catheter 14 includes a shaft 26 and one or more acoustic sensors 28 positioned on or within the shaft 26. The acoustic sensors 28 may be positioned at predetermined locations from the distal end of the shaft 26 and / or from the tip 30 of the distal end of the catheter 14. After the catheter 14 is introduced into the mammal 22 through a natural orifice or surgical orifice 32, etc., the acoustic source 12 and the catheter 14 may be localized and / or aligned with each other using an acoustic signal 34 generated by the acoustic source 12 and received by the acoustic sensors 28 on the catheter 14. For example, the time-of-flight (ToF) and / or amplitude (e.g., maximum value) of the acoustic signal 34 may be used to localize and / or align the acoustic source 12 and the catheter 14. The catheter 14 may be positioned within an anatomical structure of the mammal 22, such as an anatomical channel 38 (e.g., urethra, rectum, or blood vessel), viscera, or other anatomical structure. The catheter 14 may be positioned near a target volume 40 that can be the target of treatment and / or medical procedures. Using the catheter 14, guidewires, tools, acoustic enhancers (e.g., artificial microbubbles), fluids, and / or therapeutic substances can be introduced into or near the target volume 40. For example, acoustic enhancers can be used to promote the breakdown of calcifications such as urinary tract stones and kidney stones at low pressure amplitudes by promoting localized cavitation.

[0028] The acoustic sensor 28 is electrically coupled to the detector 42 (for example, via a cable or wire 36 (generally a cable)) and can detect and / or analyze acoustic signals (e.g., acoustic signal 34) received by the acoustic sensor 28 and converted into electrical signals by the acoustic sensor 28. Alternatively, the electrical signal data representing the acoustic signals received by the acoustic sensor 28 can be transmitted wirelessly to the detector 42. Wireless transmission can be performed using a local wireless protocol such as Bluetooth®, a local wireless network such as WiFi, a wide-area wireless network such as a cellular network, or other wireless transmission networks or protocols.

[0029] The detector 42 may have a computer, a treatment console (e.g., part of a treatment console), a data acquisition board, an oscilloscope, or any other device that pre-tunes and / or detects acoustic signals received by the acoustic sensor 28. In some embodiments, the detector 42 and the controller / power supply 25 may be combined, for example, in a treatment console.

[0030] Figure 2 is an isometric view of a catheter 14 according to one embodiment. The shaft 26 has a proximal end 201 and a distal end 202. The shaft 26 may extend parallel to the axis 204 from the proximal end 201 to the distal end 202. The shaft 26 may be flexible and / or bendable so as to include one or more curved and / or bent sections.

[0031] The housing 210 is located on and / or mounted on the proximal end 201 of the shaft 26. The housing 210 is also referred to as a connection hub or handle. The housing 210 can enclose the electrical connection between the acoustic sensor 28 and the cable 36. The proximal end of the cable 36 may include an electrical plug 220 that can be electrically connected to the detector 42. The housing 210 may also include one or more ports for connecting to each channel in the shaft 26.

[0032] Figure 3 is an enlarged view of region 300 in Figure 2, corresponding to the distal end of catheter 14. In this embodiment, the acoustic sensor 28 includes a first acoustic sensor 381 and a second acoustic sensor 382. In other embodiments, the acoustic sensor includes only the first acoustic sensor 381 or the second acoustic sensor 382. In other embodiments, the acoustic sensor 28 includes three or more acoustic sensors.

[0033] The first acoustic sensor 381 includes a first piezoelectric polymer film 391 wrapped around the inner tube 310 of the shaft 26 and / or positioned on the inner tube 310. The second acoustic sensor 382 includes a second piezoelectric polymer film 392 wrapped around the inner tube 310 of the shaft 26 and / or positioned on the inner tube 310. The shaft 26 includes an outer tube 312 positioned to cover the inner tube 310. For illustrative purposes only, the outer tube 312 is shown not to extend to the distal end 202 of the shaft 26 so as not to obscure the first and second sensors 381, 382. However, the outer tube 312 may extend to the distal end 202 of the shaft 26 (e.g., the proximal end of the tip 30). The outer tube 312 can be configured to cover the first and second sensors 381, 382, ​​which include the first and second piezoelectric polymer films 391, 392, so that the first and second sensors 381, 382 (and the first and second piezoelectric polymer films 391, 392) are located between the inner tube 310 and the outer tube 312. The inner tube 310 and the outer tube 312 are coaxial.

[0034] Electrical leads 321 and 322 are arranged on the inner tube 310. The distal end of each electrical lead 321 and 322 is electrically connected to one or both of the first and second sensors 381 and 382, ​​respectively (e.g., one or both of the first piezoelectric polymer film 391 and / or the second piezoelectric polymer film 392). The proximal end of each electrical lead 321 and 322 is electrically connected to one or more electrical contact pads 325. In some embodiments, the proximal end of each electrical lead 321 and 322 is electrically connected to their respective electrical contact pads 325. In some embodiments, there may be more than two electrical leads 321 and 322, such as three or more electrical leads electrically connected to the electrical contact pads 325. In one embodiment, there are three electrical leads (including, for example, electrical leads 321 and 322) and three electrical pads 325, with each lead electrically connected to its respective electrical pad 325. Electrical wires may be electrically connected to the electrical pad 325 and the electrical connection points within the housing 210. The electrical wires may be positioned between the inner tube 310 and the outer tube 312.

[0035] The first and second piezoelectric polymer films 391 and 392 have or consist of piezoelectric polymers such as polyvinylidene fluoride (PVDF), Pb(Zr,Ti)O3 (PZT), AlN poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) copolymer, BaTiO3 / PVDF-TrFE, ZnO film, Zr2P2BrCl, M2CO2, and / or other piezoelectric polymers. Piezoelectric polymers such as PVDF are polarizable fluoropolymers that exhibit strong and stable piezoelectric and pyroelectric activity in polar forms (e.g., β-phase). Ferroelectricity is the property of having an autogenerating polarity that can be reversed by the application of an external electric field. This property is typically found in materials having a non-centrosymmetric crystal structure in which dipoles are formed and switched within the crystal.

[0036] For example, piezoelectric polymer films containing or composed of PVDF can provide low-cost ultrasonic performance with consistent reproducibility between units. PVDF films can offer a wide frequency bandwidth with low Q-factor and low electrical impedance (e.g., 30-100 ohms). Furthermore, because PVDF films are lightweight and flexible, they conform to the cylindrical surface of catheters 14 (e.g., inner tube 310). PVDF films can also provide excellent acoustic matching with liquids and / or biological tissues.

[0037] PVDF films are mechanically robust and can be used in structural and coating applications where piezoelectric properties are not particularly required. In one embodiment, the shaft 26 (or a portion of the shaft 26) can be formed from PVDF (or other piezoelectric polymer material), and the acoustic sensor 28 can be formed by depositing electrodes at specific locations on the PVDF structure.

[0038] The enlarged view also shows that the tip 30 is tapered, which facilitates the easy passage of the catheter 14 along or through anatomical features such as tubes (e.g., blood vessels) or ureters. The tip 30 includes an opening 330 which is connected to one or more channels defined in the inner tube 310.

[0039] Figure 4A is a cross-sectional view of the shaft 26 in plan 401 of Figure 3. This cross-section is the portion of the shaft 26 between the electrical pad 325 and the proximal end 201 of the shaft 26. This cross-sectional view shows that one or more (e.g., multiple) wires 400 or other electrical conductors are arranged between the inner tube 310 and the outer tube 312. In the illustrated embodiment, there are three wires 400. In other embodiments, there may be only one, two, four, or any other number of wires 400. The wires 400 may be electrically connected to each electrical pad 325. In some embodiments, one wire 400 may be electrically connected to multiple electrical pads 325, and / or multiple wires 400 may be electrically connected to the same electrical pad 325.

[0040] The wires 400 can be electrically insulated or exposed. Furthermore, an insulating material 420 may be placed between the inner tube 310 and the outer tube 312, and this insulating material 420 may surround each wire 400 to provide them with electrical insulation. The insulating material 420 can also improve the mechanical strength of the shaft 26.

[0041] One or more channels 430 are defined by at least the inner diameter 410 of the inner tube 310. The channels 430 can be used to introduce guidewires, tools, acoustic enhancers (e.g., artificial microbubbles), fluids, and / or therapeutic substances into or near a target volume. The channels 430 extend to the opening 330 of the tip 30.

[0042] The inner tube 310 has a wall 440, which has an inner tube thickness defined by the difference between the outer diameter 412 and the inner diameter 410 of the inner tube 310. The radial thickness of the wall 440 can have local regions 442 of one or more increased thickness compared to the inner tube thickness. For example, a local segment 444 of the wall 440 can have a larger local outer diameter or outer radius compared to the outer diameter 412 (or outer radius). The local region 442 can be a region (e.g., an extrusion region) where additional material forming the wall 400 is extruded during manufacturing. The local region 442 can increase the structural strength and / or stiffness of the inner tube 310 and increase the structural strength and / or stiffness of the entire shaft 26. Furthermore, or alternatively, the local region 442 can be placed between adjacent wires 400 to physically separate and electrically insulate the wires 400.

[0043] The outer tube 312 has a wall 450, which has an outer tube thickness defined by the difference between the outer diameter 452 and the inner diameter 454 of the outer tube 312. A gap 460 is defined between the outer diameter 412 of the inner tube 310 and the inner diameter 454 of the outer tube 312. The wire 400, insulating material 420, and local region 442 are placed in the gap 460.

[0044] In other embodiments, for example, as shown in Figure 4B, a cross-sectional view of the shaft 26 in plan 401 of Figure 3 according to another embodiment, the local region 442 may be located on the wall 450 of the outer tube 312 instead of the wall 440 of the inner tube 310. The local region 442 increases the structural strength and / or rigidity of the outer tube 312. The cross-section shown in Figure 4B is the same as the cross-section shown in Figure 4A, except for the location of the local region 442, so not all features of the cross-section shown in Figure 4B are referenced as in Figure 4A. In other embodiments, the local region 442 may be located on both the wall 450 of the outer tube 312 and the wall 440 of the inner tube 310.

[0045] In other embodiments, as shown in Figure 4C, the local region 442 can be replaced by a spacer 462, which is configured as an independent element and does not need to be a component of the wall 450 of the outer tube 312 and / or the wall 440 of the inner tube 310. The number, shape, and position of the local regions 442 or spacers 462 can be modified as will be apparent to those skilled in the art. Alternatively, the local regions 442 or spacers 462, or both, can be removed.

[0046] Figure 5 is a cross-sectional view of the shaft 26 in plan 402 of Figure 3. The cross-sectional view shown in Figure 5 shows that three electrical leads 321-323 are positioned in the gap 460 between the wall 450 of the outer tube 312 and the wall 440 of the inner tube 310. In other embodiments, there may be additional or fewer electrical leads 321-323. The local region 442 is shown positioned on the wall 440, but as described above, it may be on the wall 450 instead of the wall 440, or in addition to the wall 440. Alternatively, the local region 442 can be replaced by a spacer 462 or removed.

[0047] The cross-section shown in Figure 5 is the same as the cross-section shown in Figure 4A, except that wire 400 is replaced by electrical leads 321-323. Therefore, not all features of the cross-section shown in Figure 5 are denoted by the same reference numerals as in Figure 4A.

[0048] Figure 6A is a cross-sectional view of the shaft 26 in plan 403 of Figure 3. The cross-sectional view shown in Figure 6A shows that the second piezoelectric polymer film 392 is positioned in the gap 460. The second piezoelectric polymer film 392 can be positioned around the circumference of the wall 440 of the inner tube 310 and / or cover the circumference of the wall 440. In other embodiments, the second piezoelectric polymer film 392 can be positioned around and / or cover a portion of the circumference of the wall 440 (e.g., an arc), for example, in a range of about 30% to about 75% of the circumference of the wall 440 (including any value or range in between). The local region 442 and spacer 462 do not extend to this portion of the shaft 26, thereby allowing the second piezoelectric polymer film 392 to be positioned around and / or cover the inner tube 310 without forming an air gap and / or minimizing the air gap. For good acoustic transmission, it is necessary that there is no (or that the air gap is minimized) between the outer tube 312 and the sensor (e.g., the second piezoelectric polymer film 392). This can be achieved, for example, by filling the gap 460 with one or more materials 600 having an acoustic impedance that matches (e.g., within about 20%) the impedance of bodily fluids and / or tissues having an acoustic impedance similar to that of water. In other embodiments, as shown in Figure 6B, the air gap may be eliminated or reduced by locally increasing the diameter of the inner tube 310, thereby causing the second piezoelectric polymer film 392 to be in direct physical contact with the outer tube 312 and the inner tube 310. In other embodiments, as shown in Figure 6C, the air gap can be eliminated or reduced by positioning the second piezoelectric polymer film 392 around the inner diameter of the outer tube 312 and / or covering the inner diameter. The gap 460 between the second piezoelectric polymer film 392 and the inner tube 310 can be filled with one or more materials 610 that have high acoustic impedance and / or can provide an acoustically rigid interface to increase the acoustic pressure at the acoustic sensor.In some embodiments, material 610 can be configured to absorb acoustic waves. Partial or complete absorption of acoustic waves (e.g., by epoxy resin) can reduce or eliminate the reflection of acoustic waves, which may be desirable in some embodiments.

[0049] In some embodiments, as shown in Figure 6D, two piezoelectric polymer films 392, 692 can be stacked and arranged around the wall 440 of the inner tube 310. By applying a reverse bias to one of the two piezoelectric polymer films, electromagnetic interference (EMI) can be reduced and the signal-to-noise ratio (SNR) can be increased. The piezoelectric polymer films 392, 692 may be the same or different from each other. To eliminate or reduce air gaps, as shown in Figure 6B, the outer piezoelectric polymer film 692 may be in direct physical contact with the outer tube 312, or any gap between the outer piezoelectric polymer film 692 and the outer tube 312 may be filled with one or more materials 600, as shown in Figure 6A. Furthermore, or alternatively, as shown in Figure 6C, any gap between the inner piezoelectric polymer film 392 and the inner tube 310 may be filled with one or more materials 610. The inner piezoelectric polymer film 392 and the outer piezoelectric polymer film 692 may be in direct physical contact with each other. The inner piezoelectric polymer film 392 may be in direct physical contact with the inner tube 310.

[0050] Although the local region 442 is shown positioned on wall 440, as described above, it may be located on wall 450 instead of wall 440, or in addition to wall 440. Alternatively, the local region 442 may be replaced by spacer 462, or removed altogether.

[0051] The cross-sections shown in Figures 6A to D are the same as those shown in Figures 4A, 4B, or 4C, except that the wire 400 is replaced by a piezoelectric polymer film 392 and an optional piezoelectric polymer film 692, the insulating material 420 is replaced by an acoustically transparent material 600, or the gap 460 is eliminated by increasing the diameter of the inner tube 310. Therefore, all features of the cross-sections shown in Figures 6A to D are not denoted by reference numerals as in Figures 4A to C.

[0052] The cross-section in plane 404 of Figure 3 can be the same as any of the cross-sections shown in Figures 6A to D, except that in the cross-section in plane 404, the second piezoelectric polymer film 392 is replaced by the first piezoelectric polymer film 391.

[0053] Figure 7 is a top view of the housing 210 with the top cover removed and the interior of the housing 210 exposed. Electronic equipment 700 is housed in the housing 210. Electronic equipment 700 may include devices having their own housings and / or electrical circuits mounted on a printed circuit board (PCB) 710. For example, wire 400 electrically connected to an electrical contact pad 325 (Figure 3) may be electrically connected to the electronic equipment 700 (e.g., PCB 710). Electronic equipment 700 may include electrical circuits for pre-tuning signals, improving the signal-to-noise ratio of signals, and / or eliminating common-mode electromagnetic interference. In some embodiments, the electrical circuits may include one or more signal preamplifiers, common-mode chokes, and / or common-mode rejection transformers. Wire connections within the housing 210 (e.g., connections between wire 400 and the electronic equipment 700) may be direct to provide direct current (DC) continuity, or indirectly by capacitive and / or inductive coupling to transmit only alternating current (AC). Furthermore, the electrical circuit can be used to electrically isolate the acoustic sensor 28 from the detection circuit (for example, within an external detector such as the detector 42 (Figure 1)) by using isolation devices such as isolation transformers or optical couplers.

[0054] An optional cable 36 is electrically connected to the PCB 710 and can receive electrical signals after they have passed through the electronic equipment 700. Thus, the housing 210 can provide a physical and electrical transition point from the delicate wire 400 connected to the acoustic sensor 28 to the more robust electrical cable 36. The cable 36 can be permanently connected to the housing using other connectors or, for example, a tension relief device 736. Furthermore, or alternatively, the electrical signal data representing the acoustic signals received by the acoustic sensor 28 can be transmitted wirelessly using a wireless communication circuit 750 mounted on and / or electrically coupled to the PCB 710. The wireless transmission circuit 750 can be configured to transmit using a local wireless protocol such as Bluetooth®, a local wireless network such as WiFi, a wide-area wireless network such as a cellular network, or other wireless transmission networks or protocols.

[0055] The housing 210 may include a port 720 having an opening 722 connected to a channel 330 in the shaft 26. The port 720 may be configured to connect to a tube or syringe, for example, using a Luer lock fitting 724. The Luer lock fitting 724 is shown as a female fitting, but in other embodiments it may be a male fitting. The Luer lock fitting 724 can provide a leak-free connection to a standard male tapered fitting of a syringe tip and / or other liquid transfer device.

[0056] Through the opening 722, a guidewire, tool, acoustic enhancer (e.g., artificial microbubbles), fluid, and / or therapeutic material can be inserted and exited through the channel 430 and out of the opening 330 of the tip 30 (Figure 3), for example, to be positioned in or near the target volume 40.

[0057] The housing 210 may include pins 730 for releasably attaching the front and rear (not shown) surfaces 740 of the housing 210. The internal space 742 of the housing 210 can be potted to provide fluid sealing (for example, for liquids and / or gases) and to improve the mechanical and electrical robustness of the final assembly.

[0058] Figure 8 is a flowchart of a method 80 for locating the acoustic source 12 and the catheter 14 relative to each other.

[0059] In step 801, the catheter 14 is inserted into the natural or surgical orifice 32 of the mammal.

[0060] In step 802, the acoustic source 12 is acoustically coupled to a mammal 22, such as a human. The acoustic source 12 can be placed directly on the mammal 22 (for example, on the skin 20 of the mammal 22) to acoustically couple to the mammal 22. Alternatively, an acoustic transmission medium 24, such as water, a water cushion, an acoustic coupling oil, and / or an acoustic coupling gel, can be placed between the acoustic source 12 and the skin 20 (for example, in direct physical contact) to improve acoustic transmission and coupling. The acoustic source 12 can be acoustically coupled at a position on the mammal 22 corresponding to the target position of the introduced catheter 14.

[0061] In step 803, an acoustic signal 34 is generated by one or more acoustic transducers 18 of the acoustic source 12. If the acoustic signal 34 is generated by multiple (for example, two or more) acoustic transducers 18, the acoustic signal 34 is generated sequentially by each acoustic transducer 18.

[0062] The acoustic source 12 may include an array of acoustic transducers 18 or other configurations. The array may include one row (e.g., a linear array) or two or more rows of acoustic transducers 18. In some embodiments, the symmetry of the acoustic transducers 18 can be broken by positionally offsetting one of the acoustic transducers 18 relative to the linear array.

[0063] Figure 9 shows an exemplary linear array of acoustic transducers 18 in an acoustic source 12 and an exemplary catheter 14 simplified into a cylindrical shape for illustrative purposes. The acoustic signal 34 is generated sequentially by the first and last (numbered 1 and 12) acoustic elements. In other embodiments, the acoustic signal 34 may be generated sequentially by other acoustic transducers 18 and / or additional acoustic transducers 18. In other embodiments, the acoustic signal 34 is generated by only one acoustic transducer 18.

[0064] In step 804, an acoustic signal 34 is received by an acoustic sensor 28 on or inside the catheter 14. For example, in Figure 9, the acoustic signal 34 is received by a first acoustic sensor 901 and a second acoustic sensor 902. If the acoustic signal 34 is generated sequentially by multiple acoustic transducers 18, the acoustic signal 34 is received sequentially from each acoustic transducer 18 by the first acoustic sensor 901 and the second acoustic sensor 902.

[0065] In step 805, the Time of Flight (ToF) of the acoustic signal 34 transmitted between the acoustic transducer 18 and the acoustic sensor 28 is determined. The ToF can be determined by a detector 42, such as a computer, which is electrically coupled to the acoustic sensor 28 and communicates electrically and / or electromagnetically (e.g., wirelessly). The detector 42 is electrically coupled to the controller 25 and / or the acoustic source 12 and can communicate electrically and / or electromagnetically (e.g., wirelessly). Information from the detector 42 can be transmitted to the processing unit and / or display device.

[0066] ToF can be determined as the time it takes for the acoustic signal 34 to arrive at the acoustic sensor 28 in response to a trigger signal provided by the controller 25. Alternatively, ToF can be determined by measuring the time delay between the transmitting and receiving signals. Alternatively, since the acoustic sensor 28 typically detects both the acoustic signal and the EMI induced during the transmission of the acoustic signal 34 by the transmitting acoustic transducer 18, such as a treatment head, ToF can also be determined from the receiving signal alone. The delay between the EMI and the acoustic signal detected by the acoustic sensor 28 can be used to determine ToF.

[0067] The delay between a transmitted signal and a received signal can be measured by finding the maximum value of the cross-correlation function between the transmitted and received signals. Alternatively, the delay can be determined as the time difference between several detectable characteristic features in the transmitted and received signals. These characteristic features may include the maximum amplitude, or a specific threshold level, such as a range of approximately 10% to 50% of the maximum amplitude. Characteristic features may also include signal peaks, troughs, and / or zero crossings. These features can be used individually or in combination using a sequence at one or more frequencies. Furthermore, characteristic features can be generated in an acoustic wave, for example, using amplitude, phase, and / or frequency modulation. Combining these techniques can improve the accuracy of delay time measurements.

[0068] In yet another embodiment, the sensor's position can be determined by considering the difference in arrival times from different transducer elements. This difference lies on a hyperbola with foci at the transducer positions. Different pairs of transducers give different hyperbolas. The intersection of these hyperbolas indicates the sensor's position. The mathematical formulation is similar to that used in hyperbolic navigation.

[0069] In step 806, the distance between each acoustic sensor 28 and each acoustic transducer 18 is determined. The distance can be determined by multiplying the ToF of each by the speed of sound in soft tissue, and this speed of sound in soft tissue can be approximated as the speed of sound in water. The speed of sound in water at normal body temperature (37°C or 98.6°F) is 1524 m / s, which is about 2.6% faster than the speed of sound at room temperature (20°C).

[0070] In step 807, the catheter 14 and the acoustic source 12 are localized relative to each other. The localization resolution may vary depending on the number and / or configuration of the acoustic transducers 18, including the number of transducer elements of the acoustic transducer 18 that generates the acoustic signal 34, and / or the number of acoustic sensors 28. Note that localization is performed with or without acoustic (e.g., ultrasound) imaging. The relative positions of the acoustic source 12 and the catheter 14 can be displayed on a display screen 44 (Figure 1) which is wirelessly or electrically communicated with the detector 42.

[0071] In some embodiments, steps 803-807 can be repeated (808) during medical procedures or other situations. Furthermore, or alternatively, the catheter 14 can be used to monitor the amplitude and / or other characteristics of the therapeutic ultrasound (or other acoustic energy) generated by the acoustic source 12. The catheter 14 can also be used to introduce guidewires, tools, acoustic enhancers (e.g., artificial microbubbles), fluids, and / or therapeutic substances. Furthermore, or alternatively, steps 803-807 can be repeated (808) until the positioning (e.g., roll, slide, and depth) reaches or is within the target range. After the catheter 14 and acoustic source 12 are positioned within the target range, the position of the acoustic source 12 can be fixed or locked, for example, using positioning accessories.

[0072] Figure 9 shows an exemplary localization method. A reference axis 913 is positioned along the surface of an exemplary linear array of acoustic transducers 18 of the acoustic source 12. Lines 921 and 922 represent the radial distances from the reference axis 913 to the first and second acoustic sensors 901 and 902 on the catheter 14, along their respective radial lines. Lines 921 and 922 are perpendicular to the reference axis 913 and oriented at angles 925 and 926, respectively, which may be the same or different from each other depending on the orientation of the catheter 14. Angles 925 and 926 represent the angular coordinates of the first acoustic sensor 901 and the second acoustic sensor 902 in a cylindrical coordinate system having the longitudinal axis 913.

[0073] By measuring the ToF of the acoustic signal 34 from the acoustic transducer 18 to the first and second acoustic sensors 901 and 902, the distance between the first and second acoustic sensors 901 and 902 and the acoustic transducer 18 (e.g., the reference axis 913) can be determined. Using any pair of acoustic transducers 18, the following two coordinates of the first and second acoustic sensors 901 and 902, namely the axial coordinates 923 and 924 along the reference axis 913, and the radial distances 921 and 922 from the reference axis 913 can be determined. For example, the distances from the acoustic elements 1 and 12 of transducer 18 to the first and second acoustic sensors 901 and 902 are shown by the dashed lines 917 to 920. By considering the triangle formed by lines 917 and 919 and the line connecting acoustic elements 1 and 12 of transducer 18 (for example, part of line 913), the radial distance 921 between the first acoustic sensor 901 and the reference axis 913 can be determined. Similarly, by considering the triangle formed by lines 918 and 920 and the line connecting acoustic elements 1 and 12 of transducer 18, the radial distance 922 between the second acoustic sensor 902 and the reference axis 913 can be determined.

[0074] Figure 10 shows an exemplary localization method according to another embodiment. Figure 10 shows a cylindrical coordinate system having a reference axis 1013 that extends along or passes through the catheter 14, in this example the catheter 14 is stationary while the acoustic transducer 18 is movable. Lines 1021 and 1022 represent the radial distances from the reference axis 1013 to the acoustic elements 1 and 12 of the transducer 18, respectively, along their respective radial lines. The distances from the acoustic elements 1 and 12 of the transducer 18 to the first and second acoustic sensors 901 and 902 are shown by dashed lines 1017-1020. The radial distance 1021 from the reference axis 1013 to acoustic element 1 can be determined by considering the triangle formed by lines 1017 and 1018 and line 1023 (e.g., part of the reference axis 1013) connecting the first acoustic sensor 901 and the second acoustic sensor 902. Similarly, the radial distance 1022 from the reference axis 1013 to the acoustic element 12 can be determined by considering the triangle formed by lines 1019, 1020, and 1023. Lines 1021 and 1022 are generally in a skew position; that is, the triangle formed by lines 1017, 1018, and 1023 is not necessarily coplanar with the triangle formed by lines 1019, 1020, and 1023.

[0075] One potential problem with the exemplary localization method shown in Figures 9 and 10 is that the symmetry of the linear array of acoustic transducers 18 can make it difficult to solve all three coordinates for each position of each acoustic sensor 901, 902. All elements of the linear array transducer are arranged along a single line. The symmetry of the linear array arrangement can lead to problems with complete three-dimensional position resolution. This problem is illustrated, for example, with reference to Figure 9. Only two independent coordinates can be determined by measuring the distance between each pair of acoustic sensors 901, 902 and any pair of acoustic transducers 18. In a cylindrical coordinate system, these coordinates are the position along the reference axis (or longitudinal axis) 913 and the radial distance from the reference axis 913 (e.g., along lines 921, 922). For example, for the first acoustic sensor 901, the radial distance from the reference axis 913 is shown as 921. The dashed lines 917 and 919 connect the first acoustic sensor 901 to acoustic elements 1 and 12, respectively, representing the distances between the first acoustic sensor 901 and acoustic elements 1 and 12. Even considering other collinear elements (e.g., any of acoustic elements 2-11), the angular coordinate 925, which is the third independent coordinate in the cylindrical coordinate system, cannot be solved because all transducer elements are collinear and coplane with lines 917 and 919. Additional information is needed to determine the angle 925.

[0076] In one embodiment, problems related to the symmetry of the linear array arrangement can be solved using a 2D or 3D arrangement of acoustic sensors 28 (e.g., acoustic sensors 901, 902) and / or acoustic transducers 18. For example, the catheter 14 may have three or more non-collinear acoustic sensors 28. Alternatively, the acoustic transducers 18 can be arranged on a 2D surface or a 3D shape. Note that to solve the symmetry problem, it is sufficient to break the symmetry of the linear array by separating, dividing, or adding one or more elements in a direction perpendicular to the longitudinal axis of the linear array (reference axis 913 in Figure 9). For example, the acoustic transducers 18 can be arranged as a 2D or 3D array. Alternatively, one or more additional acoustic transducers 18 can be added so as to be non-collinear with respect to the linear array.

[0077] Another method for localization involves using a known distribution of the acoustic field generated by a given transducer. By comparing the known acoustic distribution with measurements of the acoustic signal from a catheter sensor (such as acoustic sensor 28), the position of the catheter in the acoustic field can be determined. As an example of this common method, a third independent coordinate can be evaluated using the known angular dependence of the acoustic signal. For example, in Figure 9, such a third coordinate is the angular coordinate 925, 926 in cylindrical coordinate system. As shown in Figure 9, the linear array acoustic transducer 18 has a finite thickness in the direction perpendicular to the reference axis 913. Therefore, these elements can generate an acoustic field with a specific pattern characterized by angular dependence. The angular dependence can affect both the acoustic amplitude and / or the duration of the acoustic signal. The angular coordinates 925, 926 can be determined by comparing the angular dependence with measurements of the acoustic signal.

[0078] Another method for localization is to space the acoustic sensors 28 (e.g., acoustic sensors 901, 902) attached to the catheter 14 by a known distance. This distance provides an additional constraint that reduces ambiguity in localization. For example, consider a catheter with two sensors and a linear array transducer as shown in Figure 9. The positions of the first acoustic sensor 901 and the second acoustic sensor 902 are represented by axial coordinates 923, 924, radial distances 921, 922, and angles 925, 926, respectively. As mentioned above, in ToF measurement, the axial coordinates 923, 924 and radial distances 921, 922 can be determined, but angles 925, 926 cannot be determined due to the symmetry of the linear array transducer. By using the known distance between the first acoustic sensor 901 and the second acoustic sensor 902, the angle between the reference axis 913 and the direction of the catheter can be evaluated to determine angles 925, 926.

[0079] It should be noted that if the catheter 14 contains only one acoustic sensor 28, it is difficult to determine the orientation of the catheter 14. The distance between the catheter 14 and the acoustic source 18 can be determined. Referring to Figure 9, assuming that the catheter 14 contains only the first acoustic sensor 901, the radial distance along the radius line 921 and the axial coordinates 923 of the first acoustic sensor 901 (e.g., the axial coordinates of the radius line 921) can be determined when at least two acoustic transducers 18 generate acoustic signals 34. The angle 925 of the first acoustic sensor 901 (e.g., the angle of the radius line 921) can be determined, for example, using the angular dependence of the acoustic signal on the orientation of the acoustic transducer 18 as described above.

[0080] In some embodiments, the detector 42 can use positioning data to generate an output signal that causes the robot positioner 1510 (Figure 15) to position the acoustic source 12 relative to the catheter, for example, to align the acoustic source 12 with the catheter 14. The robot positioner 1510 and the detector 42 can communicate wirelessly, electrically, or both.

[0081] Figure 11 is a flowchart of a method 1100 for locating the acoustic source 12 and the catheter 14 relative to each other, according to another embodiment.

[0082] In step 1101, the catheter 14 is inserted into the natural or surgical orifice 32 of the mammal.

[0083] In step 1102, the acoustic source 12 is acoustically coupled to a mammal 22, such as a human. The acoustic source 12 can be acoustically coupled to the mammal 22 by placing it directly on the mammal 22 (for example, on the skin 20 of the mammal 22). Alternatively, acoustic transmission and acoustic coupling can be improved by placing an acoustic transmission medium 24 (for example, water, a water cushion, an acoustic coupling oil, and / or an acoustic coupling gel) between the acoustic source 12 and the skin 20 (for example, in direct physical contact).

[0084] In step 1103, a broad transcutaneous ultrasound beam is generated to determine the distance from the skin to the catheter by measuring the Time of Flight (TF) between the acoustic transducer 18 and the acoustic sensor 28. In step 1104, the distance between the acoustic transducer 18 and the acoustic sensor 28 is determined using the TF. In step 1105, the focal length of the acoustic beam generated by the acoustic transducer 18 is set based on the measured distance (e.g., the distance from the skin to the catheter).

[0085] In step 1106, the acoustic transducer 18 generates an acoustic signal 34 focused to the focal length determined in step 1104. If the acoustic source 12 includes only one acoustic transducer 18, the acoustic transducer 18 may include an adjustable acoustic lens and / or mechanical means for changing the focal length. The acoustic source 12 is aligned with the catheter 14 by searching for a first maximum amplitude signal measured by the acoustic sensor 28 while being moved or translated parallel to the Y axis of the XYZ coordinate system shown in Figure 12. The first maximum amplitude signal corresponds to a first positioning, e.g., a first coordinate (e.g., with respect to the Y axis) and the corresponding position of the acoustic source 12 on the mammal 22 (e.g., with respect to the Y axis). In step 1107, once the acoustic source 12 is aligned with the acoustic sensor 28, the acoustic field on the acoustic source 12 is switched to a sweep-focused beam, while the acoustic source 12 remains at the position along the Y axis corresponding to the first maximum amplitude signal. The focused beam can be swept by moving the acoustic source 12 parallel to the Y-axis and / or by electronically changing the focal position (for example, by changing the relative phase of the acoustic transducer 18 in the phased array). This causes the acoustic beam to sweep along or parallel to the X-axis of the XYZ coordinate system shown in Figure 12.

[0086] In step 1108, the acoustic source 12 is rotated around the transducer axis to find the direction in which the signal on the acoustic sensor 28 is maximized, indicating that the treatment head and the catheter in the ureter are properly aligned. In step 1109, the aligned acoustic source 12 is fixed in place (for example, in the position corresponding to the first maximum amplitude signal), and the treatment procedure is performed. The acoustic source 12 can be fixed in place by mechanical devices. Note that positioning is performed without imaging, including acoustic imaging (e.g., ultrasound).

[0087] Figure 12 shows an exemplary Cartesian coordinate system with three Cartesian coordinates X, Y, and Z. The X-axis is oriented along the longitudinal axis of the acoustic source 12 (e.g., the treatment head). The Z-axis is oriented along the axis of symmetry of the acoustic source 12. The distal end 202 of the catheter 14 (Figure 2) is located at a distance Z from the acoustic source 12.

[0088] Figures 13A and 13B show exemplary traces 1301A, 1301B, 1302A, 1302B, and their respective differential signals 1303A, 1303B of two acoustic sensors 28 on catheter 14, illustrating the alignment method between the acoustic source 12 and catheter 14. One acoustic sensor 28 was mounted approximately 3 cm from the catheter tip (traces 1301A, 1301B), and the other was mounted near the tip (traces 1302A, 1302B). Catheter 14 was positioned approximately 12 cm from the acoustic source 12 along the X-axis (Z-axis) (Figure 12). This corresponds to a ToF of approximately 80 μs. The acoustic source 12 emitted a 10-cycle tone burst with a center frequency of 450 kHz. The acoustic signals received by the acoustic sensors 28 were observed within a time window of 80–120 μs. In Figure 13A, trace 1301A showed a larger acoustic signal amplitude than trace 1302A, which was detected by the transducer at the tip of the catheter. When the treatment head was moved 3 cm along the X-axis, trace 1301B decreased and trace 1302B increased. This indicates that the treatment head 12 was aligned with the tip of the catheter 14. Signal traces 1303A and 1303B show differential signals calculated by taking the difference between the signals received by the two sensors 1301 and 1302, which demonstrates a method of reducing EMI induced during the oscillation of the acoustic source 12.

[0089] Figure 14 shows signals from acoustic sensors 28 (traces 1401, 1402) attached at approximately 3 cm intervals on a catheter 14 oriented along the acoustic axis Z of the acoustic source 12. The travel time of the acoustic signal over a distance of 3 cm was 20 μs. This time delay was observed between traces 1401 and 1402, indicating that the Z-axis of the treatment head was oriented so that the acoustic axis (Z-axis, Figure 12) was aligned with the length of the catheter 14. Furthermore, the shorter arrival time of the acoustic sensor 28 closer to the tip 30 of the catheter 14 (trace 1402) compared to the arrival time of the acoustic sensor 28 further away from the tip 30 (trace 1401) indicates that the tip 30 of the catheter 14 was oriented towards the acoustic source 12. This orientation of the catheter 14 was confirmed visually, illustrating the proposed alignment method. Trace 1403 represents a differential signal and demonstrates a method for reducing EMI simultaneously induced in both acoustic sensors 28 during the oscillation of the treatment head (approximately 0-20 μs). The acoustic source 12 emitted a 10-cycle tone burst with a center frequency of 450 kHz. The acoustic signal received by the acoustic sensor 28 was observed in a time window of 40-100 μs. This corresponds to the ToF of the acoustic wave from the acoustic source 12 to the acoustic sensor 28.

[0090] A catheter 14 equipped with an acoustic sensor 28 can be used for guidance in medical procedures. The catheter 14 can be inserted through a micro-incision in the skin or a natural opening in the human body. Such applications include, for example, biopsies of various organs or percutaneous access to the kidney. In the case of percutaneous access, the catheter 14 can be inserted through the ureter and may have a pre-set shape to ensure that the catheter 14 is reliably positioned within the kidney. For example, the catheter 14 may be designed to easily take on a specific shape, thereby tending to be positioned in the lower part of the kidney. The ultrasound source 12 may include a guide fixture for guiding a needle that can be used in medical procedures such as biopsies or percutaneous nephrolithotomy (PCNL). The guide fixture is adjustable to be oriented to the local position of the catheter 14. The system can determine the depth of needle insertion, which may be equivalent to the measured depth or distance between the acoustic source 12 and the catheter 14. The system also ensures that the needle avoids blood vessels, which is a typical concern and / or complication during percutaneous access. An obvious advantage of catheters equipped with acoustic sensors in any potential application is the avoidance or minimization of the use of harmful X-ray radiation currently used for guidance in these procedures.

[0091] Another unique advantage of the catheter 14 equipped with the acoustic sensor 28 is that it provides absolute measurement of acoustic pressure in the treatment zone. This is important because acoustic transmission is usually affected by various factors, such as mismatches in acoustic impedance at various interfaces, low acoustic transmission through ribs and bones, differences in acoustic wave attenuation in different types of tissues, and the presence of air or gas pockets along the acoustic path. Due to these factors, the actual acoustic pressure transmitted to the treatment zone is usually unknown. This weakness can be overcome by using the catheter 14 equipped with the acoustic sensor 28.

[0092] Figure 15 is a block diagram of a system 1500 for acoustically locating an acoustic source 12 relative to a catheter 14 according to another embodiment. System 1500 is the same as system 10 (Figure 1), except that a robot positioner 1510 is electromechanically coupled to the acoustic source 12. The detector 42 can send an output control signal to the robot positioner 1510, which operates to position the acoustic source 12 in response to the relative locating of the acoustic source 12 and the catheter 14. For example, the robot positioner 1510 can align the acoustic source 12 with the catheter 14. The detector 42 and the robot positioner 1510 can be connected electrically and / or wirelessly.

[0093] Figure 16 is a partially transparent side view of a guidewire 1600 according to one embodiment. The guidewire 1600 includes a core 1610, an optional coil 1620, and one or more acoustic sensors 1628. In some embodiments, the coil 1620 can be removed. The core 1610 and the coil 1620 are coaxial and extend from the proximal end to the distal end of the guidewire 1600. The acoustic sensors 1628 can be positioned from the distal end of the guidewire 1600 and / or from the tip 1630 of the distal end of the catheter 1600.

[0094] The acoustic sensor 1628 is located between the core 1610 and the coil 1620, and is positioned around at least a portion of the core 1610. The acoustic sensor 1628 is electrically connected to a lead wire and / or wire 1640. The lead wire and / or wire 1640 may be electrically connected to one or more electrical connection points in a housing 1650 attached to the proximal end of the guide wire 1600. Note that the guide wire 1600 is not shown to scale, and in reality the housing 1650 is much further away from the tip 1630 and the acoustic sensor 1628 than shown.

[0095] The lead and / or wire 1640 can be placed or embedded within a protective coating 1660 covering the outer surface of the guide wire 1600, thereby allowing the lead and / or wire 1640 to extend parallel to the core 1610. The coil 1620 can be placed or embedded within the protective coating 1660. In other embodiments, the core 1610 is hollow, and the lead and / or wire 1640 can pass through channels within the core 1610.

[0096] The acoustic sensor 1628 can be the same as the acoustic sensor 28. Furthermore, or alternatively, the housing 1650 can be the same as the housing 210.

[0097] Figure 17A is a cross-sectional view of the guide wire 1600 in plan 1601 of Figure 16 according to one embodiment. The acoustic sensor 1628 includes a piezoelectric polymer film 1692 disposed around at least a portion of the circumference of the core 1610. The piezoelectric polymer film 1692 may be the same as the piezoelectric polymer film 392. In some embodiments (for example, as shown in Figure 6D), the acoustic sensor 1628 may include two piezoelectric polymer films.

[0098] To reduce or eliminate the gap between the protective coating 1660 and the sensor 1628 (e.g., piezoelectric polymer film 1692), the gap 1662 between the protective coating 1660 and the sensor 1628 may be filled with one or more materials 1670 having an acoustic impedance that matches (e.g., within about 20%) the impedance of bodily fluids and / or tissues having an acoustic impedance similar to that of water. Material 1670 may be the same as material 600. In other embodiments, as shown in Figure 17B, the gap can be eliminated or reduced by increasing the diameter of the core 1610 and / or increasing the thickness of the protective coating 1660, thereby causing the piezoelectric polymer film 1692 to be in direct physical contact with the protective coating 1660 and the core 1610.

[0099] The cross-section of the guide wire 1600 in plane 1602 of Figure 16 can be the same as the cross-section shown in Figure 17A or Figure 17B, but the diameter of the core 1610 in the cross-section in plane 1602 may be smaller than that of the cross-section in plane 1601.

[0100] Figure 18 is a partially transparent side view of the guide wire 1800 according to another embodiment. The guide wire 1800 is the same as the guide wire 1600 except that the acoustic sensor 1628 is located on or within the protective coating 1660.

[0101] Figure 19A is a cross-sectional view of the guide wire 1800 in plan 1801 of Figure 18 according to one embodiment. The acoustic sensor 1628 includes a piezoelectric polymer film 1692 disposed on the outer surface of the protective coating 1660. The piezoelectric polymer film is disposed around at least a portion of the circumference of the protective coating 1660. The gap 1962 between the protective coating 1660 and the core 1610 may be filled with one or more materials 1970 that have high acoustic impedance and / or can provide an acoustically rigid interface to increase the acoustic pressure at the acoustic sensor 1628. In some embodiments, the material 1970 can be configured to absorb acoustic waves. Partial or complete absorption of acoustic waves (e.g., by epoxy resin) can reduce or eliminate the reflection of acoustic waves, which may be desirable in some embodiments. The material 1970 may be the same as the material 610.

[0102] In some embodiments, the acoustic sensor 1628 may include two piezoelectric polymer films (for example, as shown in Figure 6D).

[0103] Figure 19B is a cross-sectional view of the guide wire 1800 in plan 1801 of Figure 18 according to another embodiment. The acoustic sensor 1628 includes a piezoelectric polymer film 1692 disposed within or embedded in a protective coating 1660. The piezoelectric polymer film is disposed around at least a portion of the protective coating 1660. The gap 1962 may be filled with one or more materials 1970.

[0104] Figure 19C is a cross-sectional view of the guide wire 1800 in plan 1801 of Figure 18 according to another embodiment. The acoustic sensor 1628 includes a piezoelectric polymer film 1692 disposed on the inner surface of the protective coating 1660. The piezoelectric polymer film is disposed around at least a portion of the inner circumference of the protective coating 1660. The gap 1964 between the piezoelectric polymer film 1692 and the core 1610 may be filled with one or more materials 1970.

[0105] The cross-section of the guide wire 1800 in plane 1802 of Figure 18 can be the same as any of the cross-sections shown in Figures 19A to C, but in the cross-section in plane 1602, the diameter of the core 1610 may be smaller than that in the cross-section in plane 1601.

[0106] Figure 20 is a block diagram of a system 2000 for acoustically locating an acoustic source 12 relative to a guidewire 2010 according to one embodiment. System 2000 is the same as system 10 and / or system 1500, except that the catheter 14 in systems 10 and 1500 is replaced by a guidewire 2010. Guidewire 2010 can be the same as guidewire 1600 or guidewire 1800.

[0107] The acoustic source 12 and the guidewire 2010 can be located relative to each other according to method 80 (Figure 8), or according to method 1100 (Figure 11) when the catheter 14 is replaced with the guidewire 2010.

[0108] Figure 21 shows an embodiment in which a medical device 2100 equipped with multiple acoustic sensors 2102 is inserted into the collection system of a human kidney 2120 through the ureter 2110. The medical device 2100 may be a catheter (e.g., catheter 14), a guidewire (e.g., guidewires 1600, 1800), or other medical device. The acoustic sensors 2102 may be acoustic sensor 28, acoustic sensor 1628, and / or acoustic sensor 1828.

[0109] The medical device 2100 is configured to be wound or unwound to accept a predetermined shape, for example, to form a coiled structure with a predetermined shape in the kidney 2120 or other target site, once fully inserted. The predetermined shape determines the relative position of the acoustic sensor 2102, avoiding any ambiguity that may arise regarding the sensor's position in the kidney 2120. The external acoustic source 12 is acoustically coupled to the patient's skin 2112 and generates an acoustic signal 2134. This acoustic signal 2134 is received by the acoustic sensor 2102, and, for example, a detector 42 is used to establish and / or determine the relative position between the acoustic source 12 and the acoustic sensor 2102 in the kidney 2120. The acoustic signal 2134 may be the same as the acoustic signal 34.

[0110] After the relative positions of the acoustic source 12 and the acoustic sensor 2102 located in the kidney 2120 are determined, a needle 2140 or similar medical device can be inserted into the kidney 2120 (e.g., the renal calyces or renal wall) under acoustic guidance from the acoustic source 12 and the acoustic sensor 2102, as disclosed herein, to perform, for example, a percutaneous access procedure. The relative position and orientation (e.g., angle) of the needle 2140 is known with respect to the acoustic source 12, for example, by using a needle guide or needle bracket 2142 that allows adjustment of the insertion angle of the needle 2140. This method is easy to perform and does not require special skills such as those of an ultrasound specialist. This method does not require an ultrasound imaging system or harmful ionizing radiation imaging such as X-ray imaging.

[0111] The present invention should not be considered limited to the specific embodiments described above. Various modifications, equivalent processes, and numerous structures to which the present invention can be applied will be readily apparent to those skilled in the art by examining this disclosure. The embodiments described above can be carried out in various ways. One or more aspects and embodiments relating to the execution of a process or method may be executed or controlled by program instructions executable by a device (e.g., a computer, processor, or other device).

[0112] In this regard, various inventive concepts may be implemented as non-temporary computer-readable storage media (or multiple non-temporary computer-readable storage media) (e.g., any suitable type of computer memory including temporary or non-temporary digital storage units, a circuit configuration of a field-programmable gate array or other semiconductor device, or other tangible computer storage media), such non-temporary computer-readable storage media may be encoded with one or more programs that, when run on one or more computers or other processors, perform a method of implementing one or more of the various embodiments described above. When implemented in software (e.g., as an app), the software code may run on any suitable processor or group of processors, whether provided on a single computer or distributed across multiple computers.

[0113] Furthermore, it should be understood that computers can be embodied in any of the various forms, such as rack-mount computers, desktop computers, laptop computers, or tablet computers, as non-limiting examples. Additionally, computers may be incorporated into devices that are not generally considered computers but possess suitable processing capabilities, including personal digital assistants (PDAs), smartphones, or other suitable portable or fixed electronic devices.

[0114] Furthermore, a computer may have one or more communication devices, which may be used to interconnect the computer to one or more other devices and / or systems, such as local area networks or wide area networks, such as enterprise networks, and any preferred form of network, such as an intelligent network (IN) or the Internet. Such networks may be based on any suitable technology, may operate according to any suitable protocol, and may include wireless or wired networks.

[0115] Furthermore, a computer may have one or more input devices and / or one or more output devices. These devices can, among other things, represent a user interface. Examples of output devices that can be used to provide a user interface may include a printer or display screen that presents output visually, and a speaker or other sound-producing device that presents output audibly. Examples of input devices that can be used for a user interface include a keyboard, and pointing devices such as a mouse, touchpad, and digital tablet. As another example, a computer may also receive input information through speech recognition or in other audible formats.

[0116] The non-temporary computer-readable medium may be portable so that the programs or sets of programs stored therein can be loaded onto one or more different computers or other processors to implement one or more of the various embodiments described above. In some embodiments, the computer-readable medium may be a non-temporary medium.

[0117] The terms “program,” “app,” and “software” are used herein in a general sense and refer to any kind of computer code or set of computer executable instructions that can be used to program a computer or other processor to implement the various embodiments described above. Furthermore, it should be understood that, in one embodiment, one or more computer programs that, when executed, perform the methods of this application do not need to reside on a single computer or processor, but may be modularly distributed across multiple different computers or processors to implement the various embodiments of this application.

[0118] Computer executable instructions can be executed by one or more computers or other devices in many ways, such as through program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. The functionality of program modules can be combined or distributed as needed in various embodiments.

[0119] Furthermore, the data structure can be stored in a computer-readable medium in any preferred format. For simplicity of explanation, the data structure may be shown as having fields that are related through locations within the data structure. Such relationships can also be achieved by assigning locations in the computer-readable medium that convey the relationships between the fields to the storage locations of the fields. However, relationships between the information of the fields in the data structure can be established using any preferred mechanism, which may include the use of pointers, tags, or other mechanisms for establishing relationships between data elements.

[0120] Thus, the present disclosure and claims include novel and unoriginal improvements to existing methods and techniques that have not been previously known or practiced, in order to achieve the useful results described above. Users of the methods and systems will enjoy concrete benefits from the functions enabled by the specific modifications described herein, and from the effects that such modifications bring to the user of the system and its outputs. When the inventions of the claims are implemented using the technical components described herein, it is expected that significantly improved operation can be achieved.

[0121] Furthermore, as described above, some embodiments may be implemented in one or more ways. The operations performed as part of the method can be ordered in any preferred way. Thus, although the embodiments described were shown as a series of operations, embodiments may be constructed to perform the operations in a different order than described, and this may include performing some operations simultaneously.

Claims

1. It is a catheter, The shaft and The tip portion located at the distal end of the shaft, At least one acoustic sensor disposed on or within the shaft, wherein each acoustic sensor is positioned at a distance from the distal end of the shaft, At least one electrical conductor disposed on or within the shaft, each electrical conductor electrically connects each acoustic sensor to one or more electrical connection points in a housing attached to the proximal end of the shaft, and A catheter having

2. A catheter according to claim 1, wherein each acoustic sensor has a piezoelectric polymer film arranged around at least a portion of the circumference of the shaft.

3. A catheter according to claim 2, wherein the piezoelectric polymer film has polyvinylidene fluoride.

4. In the catheter according to claim 2, The shaft includes an inner tube and an outer tube. Each of the piezoelectric polymer films is arranged around at least a portion of the circumference of the inner tube, The at least one electrical conductor is positioned between the inner tube and the outer tube. catheter.

5. In the catheter according to claim 4, The inner tube is defined by a wall, which has an inner wall thickness. One or more regions of the wall have a thickness that is increased compared to the thickness of the inner wall. catheter.

6. In the catheter according to claim 4, The outer tube is defined by a wall, which has an outer wall thickness. One or more regions of the aforementioned wall have a thickness that is increased compared to the thickness of the outer wall. catheter.

7. A catheter according to claim 4, wherein a spacer is disposed between the inner tube and the outer tube.

8. A catheter according to claim 1, wherein the one or more electrical connection points are electrically coupled to a cable extending through the housing.

9. A catheter according to claim 8, wherein the one or more electrical connection points are formed on a printed circuit board located inside the housing.

10. A catheter according to claim 8, further comprising a wireless communication circuit electrically coupled to the one or more electrical connection points.

11. A catheter according to claim 1, wherein the housing includes a port having a hole aligned with the central channel of the shaft.

12. A catheter according to claim 1, wherein the at least one acoustic sensor includes a first acoustic sensor and a second acoustic sensor, and the first sensor and the second sensor are separated by a predetermined distance.

13. A method for determining the relative positions of an acoustic source and a medical device, a. The process of introducing the medical device into a mammal, b. A step of acoustically coupling the acoustic source to the mammal at a position corresponding to the target position of the medical device, wherein the acoustic source comprises a housing and an acoustic source transducer disposed within the housing, the coupling step, c. A step of generating an acoustic signal using the acoustic source transducer, d. A step of receiving the acoustic signal by an acoustic sensor on or within the medical device, wherein the acoustic sensor communicates electrically or wirelessly with a detector, the receiving step and e. A step of determining the time of flight (ToF) of the acoustic signal transmitted between the acoustic source transducer and the acoustic sensor using the detector, f. The steps of determining the distance between the acoustic source transducer and the acoustic sensor using the Time of Flight (ToF) with the detector, g. The step of using the detector to locate the sound source and the medical device in real time relative to each other, at least partially based on the distance between the sound source transducer and the sound sensor. A method having

14. In the method according to claim 13, The aforementioned acoustic sensor is a first acoustic sensor, The medical device includes at least a second acoustic sensor, This method further, The process of receiving the acoustic signal using the first and second acoustic sensors, The steps include determining the first Time of Flight (ToF) of the acoustic signal transmitted between the acoustic source transducer and the first acoustic sensor using the detector, The steps include determining the second Time of Flight (ToF) of the acoustic signal transmitted between the acoustic source transducer and the second acoustic sensor using the detector, The detector is used to determine a first distance between the acoustic source transducer and the first acoustic sensor using the first ToF, The detector is used to determine a second distance between the acoustic source transducer and the second acoustic sensor using the second ToF, A step of positioning the sound source and the medical device relative to each other, at least partially based on the first and second distances. A method having the following characteristics.

15. In the method according to claim 13, The aforementioned medical device includes multiple acoustic sensors, The sound source includes multiple sound source transducers, This method further, A step of sequentially generating the acoustic signal using at least a first acoustic source transducer and a second acoustic source transducer among the plurality of acoustic source transducers, The process of receiving the acoustic signal using each acoustic sensor, (a) a step of determining the ToF of each of the acoustic signals transmitted between at least the first acoustic source transducer and the second acoustic source transducer and (b) each acoustic sensor, Using each Time of Flight (ToF), the process involves determining the distance between (a) each of the at least first acoustic source transducers and the second acoustic source transducers and (b) each acoustic sensor. A step of locating the sound source and the medical device relative to each other based at least partially on the respective distances. A method having the following characteristics.

16. In the method according to claim 13, The aforementioned position is the first position, The method further comprises the steps of performing at least steps b to f while the sound source is located in the first position, then moving the sound source to a second position, and repeating steps b to f while the sound source is located in the second position, thereby improving the resolution of the relative positioning of the sound source and the medical device compared to when positioning is performed while the sound source is located only in the first position, and the repeated steps A method or possession.

17. In the method according to claim 13, The aforementioned medical device has a catheter. The aforementioned catheter is introduced into the organ, This method further, The process involves introducing an acoustic enhancer proximal to the calcification using the aforementioned catheter, The process of applying acoustic energy using the aforementioned acoustic source, A step of generating cavitation with the aforementioned acoustic energy and the aforementioned acoustic enhancer to decompose at least a portion of the calcification. A method having the following characteristics.

18. The method according to claim 13, further comprising the step of adjusting the position of the sound source in accordance with the relative positioning of the sound source and the medical device by a robotic positioner communicating with the detector.

19. A method according to claim 13, further comprising the step of displaying the relative positions of the sound source and the medical device on the detector or on a display screen that electrically communicates with the detector.

20. A method according to claim 13, wherein the medical device has a catheter or a guidewire.

21. A method for locating an acoustic source and a catheter relative to each other, a. The step of introducing the catheter into a mammal, wherein the catheter is A shaft and a tip portion located at the distal end of the shaft, At least one acoustic sensor disposed on or within the shaft, wherein each acoustic sensor is positioned at a distance from the distal end of the shaft, and The process of introducing the above-mentioned process, b. A step of acoustically coupling the acoustic source to the mammal at a position corresponding to the target position of the catheter, wherein the acoustic source comprises a housing and a plurality of acoustic source transducers disposed within the housing, the coupling step, c. A step of generating a broad acoustic energy beam using the aforementioned acoustic source, d. A step of determining a measurement distance between the acoustic source transducer and the at least one acoustic sensor, wherein the measurement distance is at least partially based on the time of flight (ToF) of the acoustic signal transmitted between the acoustic source transducer and each acoustic sensor, e. A step of setting the focal length of the acoustic source transducer corresponding to the measurement distance, f. A step of generating a focused beam of acoustic energy by the acoustic source while moving the acoustic source parallel to a first axis perpendicular to the acoustic axis of the acoustic transducer, wherein the focused beam is focused to the focal length, g. A step of monitoring the output signals of at least one acoustic sensor with the detector and determining a first maximum amplitude signal while the focused beam is being generated, wherein the first maximum amplitude represents a first position determination with respect to the first axis, h. A sweeping step, after step g, wherein the focused beam is swept with respect to a second axis perpendicular to the acoustic axis of the acoustic transducer, the ultrasonic source is positioned at a position corresponding to the first maximum amplitude signal, i. A step of monitoring the output signal of at least one acoustic sensor with the detector and determining the second maximum amplitude signal while the focused beam is being swept, wherein the second maximum amplitude represents a second position determination with respect to the second axis, j. After step h, a step of rotating the focused beam with respect to the acoustic axis, k. A step of monitoring the output signal of at least one acoustic sensor with the detector and determining a third maximum amplitude signal while the focused beam is rotating, wherein the third maximum amplitude represents a third position determination with respect to the acoustic axis; A method of having.

22. A method according to claim 21, further comprising the step of locking the sound source to a position corresponding to the first maximum amplitude signal.

23. A guide wire, The core and A coil coaxially arranged on the core, A protective coating placed on the coil, At least one acoustic sensor is positioned at a distance from the distal end of the shaft, At least one electrical conductor disposed within the protective coating, each electrical conductor electrically connects each acoustic sensor to one or more electrical connection points in a housing attached to the proximal end of the guide wire, and A guide wire having

24. A guide wire according to claim 23, wherein each acoustic sensor has a piezoelectric polymer film disposed around at least a portion of the circumference of the core.

25. A guide wire according to claim 23, wherein each acoustic sensor has a piezoelectric polymer film disposed around at least a portion of the circumference of the protective film.

26. A guide wire according to claim 23, wherein each acoustic sensor has a piezoelectric polymer film disposed on the protective film.

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