Ultrasound guided procedures with integrated device tracking

Abstract

Vapor ablation systems and methods are provided. Also provided herein are integrated electromagnetic tracking systems for use with ultrasound-guided procedures such as TRUS, EUS, ICE, transvaginal, and external ultrasound. The system can include a probe comprising internalized antenna array in the probe and a device with tip-mounted coils to provide low-power, localized, motion-invariant tracking of therapeutic or diagnostic instruments.

Description

ULTRASOUND GUIDED PROCEDURES WITH INTEGRATED DEVICE TRACKINGPRIORITY CLAIMS

[0001] This patent application claims priority to U.S. provisional patent application no.63 / 775,766, titled “ULTRASOUND GUIDED PROCEDURES WITH INTEGRATED DEVICE TRACKING,” and filed on March 21, 2025, which is herein incorporated by reference in its entirety.INCORPORATION BY REFERENCE

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.BACKGROUND

[0003] Medical procedures that rely on ultrasound imaging, such as prostate interventions, liver biopsies, and cardiac mapping, require accurate real-time tracking of instruments within the patient. Conventional electromagnetic (EM) tracking systems typically use external field generator boxes and separate sensors mounted on devices. While these systems provide positional information, they often require bulky equipment, extensive setup, and repeated calibration, and they can be disrupted by nearby metal objects or patient movement.

[0004] In transrectal ultrasound (TRUS) guided procedures, such as vapor ablation therapy for prostate cancer, accurate localization of a needle tip is critical for effective treatment while avoiding damage to surrounding tissues. Current systems may require additional sensors or markers to correlate device location with the ultrasound image, and the large field generator arrays can limit workflow and obstruct the procedure.

[0005] Similarly, in other ultrasound-guided interventions, such as endoscopic ultrasound (EUS), intra-cardiac echocardiography (ICE), transvaginal ultrasound, and external ultrasound for breast, thyroid, or lymph node procedures, existing tracking solutions face similar challenges. Patient movement, metal interference, and cumbersome equipment can reduce the precision and reliability of these systems, limiting their clinical utility.

[0006] There is a need for a compact, integrated tracking solution that maintains accurate real-time instrument guidance, minimizes external interference, reduces system complexity,- 1 - SG Docket No.: 14676-705.600and supports a variety of ultrasound-guided procedures. The present disclosure addresses these needs by incorporating the tracking array directly into the ultrasound probe and providing tip-mounted device coils, enabling low-power, localized, and motion-invariant tracking.SUMMARY OF THE DISCLOSURE

[0007] Vapor ablation therapy comprises delivery of fluid in its gaseous or vapor state to tissues targeted for ablation. The vapor passes through the interstitial spaces between the targeted tissue cells and condenses onto the cell membranes, giving up its heat of vaporization in the process, which is nominally 540 calories / gram for water. The membranes are denatured, and the cells die, leaving a wet (not charred) tissue mass behind that is removed naturally over time. The targeted tissue is thereby removed from the body without surgical intervention. The references provide details of vapor ablation therapy.

[0008] Systems and methods are provided for targeting cancerous tissue within the prostate. A delivery device comprises a cartridge that converts sterile water to steam and delivers it through a needle that is guided into the prostatic urethra and delivered through the urethra wall to sites targeted for ablation. The procedures are guided by real time TRUS imaging and an electromagnetic needle guidance system (NGS). Pre-operative MRI images of the prostate are used to target the locations of cancerous tissues. One typical calorie dose (as measured in a calorimeter) is 15 calories / second for 10 seconds (150 calories). Another calorie dose is 22 calories / second for 10 seconds (220 calories). Another calorie dose is 33 calories / second for 33 seconds (330 calories).

[0009] One method for treating cancer of the prostate comprises introducing a heated vapor interstitially into the interior of a prostate, wherein the vapor controllably ablates prostate tissue. This method can utilize vapor for applied thermal energy of between 50 calories and 600 calories per individual vapor treatment (and assumes multiple treatments for each prostate lobe). The method can cause localized ablation of prostate tissue without damaging the prostatic urethra and without damaging tissue outside of the prostate gland.

[0010] The system can include a vapor delivery mechanism that delivers vapor media, including water vapor. The system can utilize a vapor source configured to provide vapor having a temperature of at least 60-140o C. The system further comprises a computer controller configured to deliver vapor for an interval ranging from 1 second to 30 seconds.

[0011] In some embodiments, the system further comprises a source of a pharmacologic agent or other chemical agent or compound for delivery before, during, or after vapor therapy. These agents include, without limitation, an anesthetic, antibiotic, toxin such as -2 - SG Docket No.: 14676-705.600Botox®, or chemical agent that can treat cancerous tissue cells. The agent also can be a sealant, an adhesive, a glue, a superglue, or the like. In some embodiments an echoic or anechoic agent may be delivered with the vapor to improve its visibility under ultrasound imaging to help, for example, in locating the needle tip on the image. For example, air or other gases are echoic.

[0012] In some embodiments, a prostate treatment device can be provided comprising an introducer shaft sized and configured for transurethral access into a patient, a vapor generator configured to generate a condensable vapor, a vapor delivery needle in communication with the vapor generator and slidably disposed within the introducer shaft, and an actuator configured to move the vapor delivery needle between a retracted position inside the introducer shaft and an extended position at least partially outside of the introducer shaft, and to advance or retract the needle continuously or in steps to tissues at any location between the prostatic urethra and prostate capsule. The entire procedure is visualized with ultrasound imaging fused with pre-operative MRI images to identify target tissues. Vapor injected into the prostate tissue is visible on the ultrasound image. Tissues on the outside of the prostate, in particular nerves that enable sexual function, are protected during vapor therapy by injecting saline into the periprostatic space around the prostate. The saline delivery needles are inserted into the prostate through the perineum, guided by real time TRUS imaging. Tools required for image guided transurethral vapor therapy are a vapor delivery device, a TRUS imaging device, an array of tracking antennae and sensors or sense coils placed both on the delivery device and on the TRUS probe, and one or more saline delivery needles.

[0013] Ultrasound image guided systems project beams of ultrasound energy from one or more arrays of ultrasound crystals through tissue to be imaged. The ultrasound beams are reflected from features in the tissue and return to the crystals which now act as receivers of the reflected energy. Received energy vs round trip travel time comprises a two-dimensional image of tissue reflectivity. Multiple arrays and / or array movements enable three-dimensional imaging. Many applications involve image guidance of a delivery device or catheter to target locations within the tissue. The ultrasound image of a therapy device may not be accurate enough for clinical requirements. This may be due to the blocking of critical parts of the device by body tissues or water vapor and / or due to the device not appearing in the plane of a 2D ultrasound image. Tracking elements placed on the interventional device and proximate to the ultrasound array enable marking the location of a device on the ultrasound image. The location may include an animation of an elongated device when both the location and orientation of the tracking element are measured in real time.-3 - SG Docket No.: 14676-705.600

[0014] Commercial medical tracking systems comprise an array of electromagnetic transmitter coils residing in a box placed outside the patient. Tens of Watts of transmit power are required to transmit measurable magnetic fields to the location of magnetic field sensors located on interventional tools and on an ultrasound array, which sensors may reside up to 50 cm away from the transmitter coils (antennae). The goal of the tracking system is to display the location(s) of device mounted sensor(s) onto the ultrasound array image, providing the user with a visual localization and tracking of his interventional tools relative to surrounding body tissues. Prior art tracking systems track both the device mounted sensors and ultrasound array mounted sensors relative to the magnetic field antennae array to provide the locations of the device mounted sensors relative to the ultrasound array. The multiple transmit antennae are energized sequentially so the needle tip sensor and ultrasound array sensor can identify each individual antennae, or they transmit at distinct frequencies that are identified in sensor Fourier Transform software.

[0015] In preferred embodiments of this disclosure, the transmit and receive coils are close enough together that the antennae can be small enough to be integrated into the ultrasound imaging array while still transmitting sufficient magnetic field strength to track devices with adequate accuracy. For example, accurate tracking of a vapor delivery needle at any location within the prostate to ablate cancerous targets is achieved using an antennae array located within a TRUS probe in the rectum using a transmit power as small as 0.1 Watts.

[0016] One aspect of the present disclosure uses the needle tip coil as a transmitter (instead of a receiver) of magnetic fields that are received by an array of coils (antennae) proximate to an ultrasound imaging array. The array of sensor coils receives transmitted data simultaneously and continuously, reducing the time for noise to enter the system, or in the case of multiple frequencies, reducing the signal bandwidth and thereby reducing noise. Thus, the signal to noise ratio is increased in this disclosure. The device mounted transmitters do not get hot because transmit power is less than 0.1 Watts. This small power is enough for robust transmitted magnetic fields to reach nearby TRUS mounted antennae, but much smaller than needed to reach an external antennae array. The TRUS antennae array may comprise an array of sensors and / or an array of transmitters. When sensors and transmitters are comprised of coils of wire they may be used as sensors and / or transmitters with the same mathematical formulas (mutual inductance formulas) expressing transmit to sense coupling.

[0017] Eddy currents induced by transmit antennae magnetic fields into metal objects near the patient generate their own magnetic fields that are detected by sense coils. It is - 4 - SG Docket No.: 14676-705.600generally difficult to compensate for eddy current sources that arise from objects of arbitrary shapes and unknown locations. In the prostate cancer application, the transmit coil and sensor coils of this disclosure are always separated by less than 10 cm during the procedure. The needle tip transmit power can therefore be less than 0.1 Watt, compared to commercial transmit coils operating in the tens of Watts. The relatively very small transmit power from the needle tip coil will induce relatively small eddy currents in metal objects near the patient, resulting in relatively much smaller interfering magnetic fields. In the prostate application, the desired overall tracking volume is smaller than 200 cubic cm, residing entirely within the patient. It is very unlikely that foreign metal objects will reside within this volume. By contrast, the roughly 125,000 cubic cm tracking volume of commercial systems, with transmitters placed outside the patient, will very likely experience metal object interference. Note that tracking accuracy may be equivalent whether the device coils are transmitters or receivers with the antennae array being either receivers or transmitters.

[0018] Since the antennae of this disclosure are mounted on the TRUS probe, needle tip tracking data is automatically given in TRUS image coordinates. Conventional systems, on the other hand, require that sensors be placed both on the needle and / or delivery device shaft, and on the TRUS probe, so that sensor tracking data can be presented relative to the TRUS image.

[0019] This disclosure provides distinct ease of use advantages. The set of receive coils in this disclosure is integrated within the TRUS probe and the sensor cable is therefore integrated with the TRUS cable. The needle tip transmit / receive coil(s) leads pass through a channel(s) in the wall of the needle and are integrated into the cable extending from the delivery device cartridge to the system console. The tracking system is thus invisible to the user. By contrast, commercial systems have one or more transmitter boxes that need to be set up, plugged into the system console or a separate box, and adjusted by the user. In many applications, leads extending from one or multiple sensors need to be plugged into the system console or a separate box. Patient movements in the prior art system may require reregistration of the tracker and / or one or more sensors attached to the patient to monitor his movements. This is because patient movements are relative to the stationary transmitter box, while the ultrasound probe moves with the patient.

[0020] In the integrated system of this disclosure the ultrasound probe (with integrated tracking antennae) and the interventional device both move with the patient so that patient movements are not an issue for tracking.

[0021] In a preferred embodiment, a set of theoretically exact equations is derived for the voltage induced in an array of rectangular sensor coils by AC current flowing in a needle tip - 5 - SG Docket No.: 14676-705.600or shaft tip transmit coil. Rectangular sense coils are selected because highly accurate analytic expressions for the sensed voltages are available. Formulas for the voltages induced in the rectangular coils located on the faces of a parallelogram by the magnetic field of an alternating current flowing in a needle tip or shaft tip transmit coil are expressed in terms of a Cartesian (x,y,z) coordinate system centered at the center of a parallelogram. As voltage data is collected, it is fit to the formulas by adjusting the assumed location and orientation of the transmit coil to find the “least squares” fit to the data.

[0022] In one preferred embodiment, a sensor cube (or other geometrical arrangement of sensors) is integrated into the manufacture of a TRUS ultrasound probe. The sensor coils are arranged for optimal tracking accuracy while never crossing the face of an ultrasound crystal. Sensor leads are integrated with TRUS crystal leads into a single cable during manufacture. The sensor coils may be wound on a cube or other geometric structure, or they may be integrated into the walls or body of the TRUS probe. Theoretically at least five sensor coils are needed to resolve the three Cartesian coordinates and two orientation angles of the transmit coil. In one preferred method in which the sensors comprise three magnetic field sensors and five sensors measuring the independent components of the magnetic field gradient tensor (eight sensors total), an exact formula is provided for the location and orientation of a magnetic dipole transmitter relative to the center of the sensing structure when the sense coil dimensions are small compared to the separation between the transmit dipole and the sensing structure.

[0023] In one preferred embodiment, two rectangular coils are placed on each of the six faces of a cube for a total of 12 rectangular coils. The magnetic field components and magnetic field gradient tensor components are expressed as combinations of the voltages induced in these 12 coils In one embodiment two sensor cubes are placed in two locations proximal and distal to the TRUS crystal arrays. Each cube may have three orthogonal sensor coils. These may be individual coils wound around the cube circumference or six coils wound on the cube faces with the outputs of the three pairs of coaxial coils summed to yield three orthogonal sensor outputs and differenced to yield the three in-line field gradients. The relatively large baseline between cubes allows for greater accuracy at all points in the space between the cubes. In addition, the formulas for the magnetic fields linking the sensor coils may be inverted analytically to provide theoretically exact solutions for the transmitter coordinates with no initialization requirements.

[0024] Coils of fine wire may be transmitters or receivers. Sensor voltage induced in a coil (sensitivity) increases with frequency below a self-resonance frequency. Transmitted magnetic fields are stronger when coils are wound around a ferrous core, however the core - 6 - SG Docket No.: 14676-705.600may add unwanted frequency or temperature dependencies and may saturate when the coil is used as a transmitter. Miniature magneto-resistive sensors are available which have good sensitivity at low frequencies, down to DC. Strong magnetic fields may be transmitted by a tiny rotating permanent magnet. Small currents in coils surrounding the magnet can generate large fields as the magnet rotates. A spherical magnet will rotate about an axis dictated by the currents in surrounding drive coils. The magnet can rotate sequentially about multiple axes, or the rotation axis can process in time over the entire range of axes. Multi -axial rotation may eliminate the need for multiple transmitters to track devices.

[0025] Conventional bi-plane TRUS arrays have the axial imaging plane at the distal end of the sagittal imaging plane. During vapor therapy it is desirable to have the ablation target tissue in the axial imaging plane. In this case, with conventional bi-plane TRUS there is little to no visualization of therapy distal to the target in the sagittal view during therapy. This disclosure greatly improves ultrasound geometry by passing the axial crystal array through the center of the sagittal array so that target tissue can be centered in both the axial and sagittal image planes.

[0026] This disclosure integrates tracking antenna with an ultrasound crystal array to provide real time ultrasound imaging guidance of a vapor ablation needle to cancer targets in the prostate. Multiple advantages include the elimination of external tracking antennae and associated equipment and equipment set-up; a system that requires no user activity (invisible to the user); improved accuracy with virtual elimination of interference from metal objects outside of the patient; elimination of a separate sensor to track the location of the TRUS crystal arrays; accurate tracking that is unaffected by patient movements; and axial and sagittal images that are centered on the ablation target.

[0027] This integrated tracking system disclosure applies equally to many other ultrasound guided interventions using Endoscopic Ultrasound (EUS); ICE (Interventional Cardiac Echo); External Ultrasound; Transvaginal Ultrasound; Intravascular Ultrasound (IVUS); etc., (in addition to Transrectal Ultrasound (TRUS)), used to guide interventional tools fortissue biopsy; placement of fiducial markers; tissue ablation using vapor, rf, water jet, microwaves, external beam radiation, surgical tools, drug delivery, fluid injection or removal, etc.

[0028] An integrated electromagnetic tracking system for guiding a device within a patient is provided, comprising: an ultrasound imaging probe comprising a tracking antenna array configured to generate a magnetic field and one or more transducer arrays configured to generate ultrasound images of a target tissue; a transurethral vapor delivery device having a shaft and a vapor delivery needle deployable from the shaft, the vapor delivery device - 7 - SG Docket No.: 14676-705.600comprising one or more sensors disposed on the shaft and / or the vapor delivery needle configured to generate signals when in the presence of the magnetic field; and a system console configured to determine a position and / or an orientation of the shaft and / or the vapor delivery needle based on the signals.

[0029] In other aspects, an integrated electromagnetic tracking system for guiding a device within a patient is provided, comprising: a transurethral vapor delivery device having a shaft and a vapor delivery needle deployable from the shaft, the vapor delivery device comprising one or more transmitters disposed on the shaft and / or the vapor delivery needle configured to generate a magnetic field; an ultrasound imaging probe comprising an antenna array configured to generate signals when in the presence of the magnetic field and one or more transducer arrays configured to generate ultrasound images of a target tissue; and a system console configured to determine a position and / or an orientation of the shaft and / or the vapor delivery needle based on the signals.

[0030] In some aspects, the probe can be a transrectal ultrasound (TRUS) probe.

[0031] In some aspects, the tracking antenna array comprises a plurality of coils

[0032] In one aspect, the system console is configured to determine the location and / or orientation of the shaft and / or the vapor delivery needle in real-time.

[0033] In one aspect, the probe and the device move with the patient to provide motioninvariant tracking.

[0034] In some aspects, the system console is configured to determine the location and / or orientation of shaft and / or the vapor delivery needle within a localized tracking volume.

[0035] In other aspects, the localized tracking volume is less than or about 200 cubic centimeters.

[0036] In some aspects, the localized tracking volume is tracked with a transmit power of less than 0.1 W.

[0037] In other aspects, the tracking antenna array comprises a plurality of coils mounted on a cube, a spherical magnet, or gradient coils.

[0038] In one aspect, the tracking antenna comprises a spherical magnet, wherein the spherical magnet has a diameter less than 3 mm and is rotatable about one or more axes to generate a dynamic magnetic field.

[0039] In some aspects, the system console provides animated visualization of the device relative to anatomy imaged by the probe.

[0040] In some aspects, the system is further configured for fusion of preoperative MRI images with real-time TRUS images to guide device placement.

[0041] In one aspect, the plurality of coils comprises 3-12 coils.- 8 - SG Docket No.: 14676-705.600

[0042] In some aspects, the tracking antenna array comprise a plurality of coils that are rectangular, free-standing, or wound on a permeable core.

[0043] In some aspects, the one or more sensors comprise one or more shaft-tip coils spaced within 2-5 cm, or up to 5 cm from a needle tip coil.

[0044] In additional aspects, the probe comprises dual or multiple antenna array cubes positioned proximal and distal to the ultrasound crystal arrays.

[0045] In some aspects, the antenna array cubes are configured to provide a baseline to enhance spatial tracking accuracy.

[0046] In some aspects, the probe comprises one or more axial crystal arrays.

[0047] In one aspect, the probe comprises one or more sagittal crystal arrays.

[0048] In some aspects, the probe comprises an axial array and a sagittal array, wherein a portion of the axial array overlaps with a portion of the sagittal array.

[0049] In one aspect, the sensors comprise one or more magnetic, fluxgate, saturable-core, or magnetoresistive sensors, or a combination thereof.

[0050] In other aspects, the system console is configured to display one or more device animations in real-time relative to multiple imaging planes.

[0051] In some aspects, the system can be used in combination with transrectal ultrasound (TRUS), endoscopic ultrasound (EUS), intracardiac echocardiography (ICE), transvaginal ultrasound, and / or external ultrasound.

[0052] In another aspect, the system is configured to deliver therapeutic agents selected from a group consisting of vapor, a pharmacological agent, and a structural agent.

[0053] In some aspects, the system includes signal processing configured to determine the location and / or orientation using least-squares fitting of sensor voltages and / or gradient tensor calculations.

[0054] A method for guiding a device within a patient is provided, comprising: inserting a probe comprising an antenna array into the patient; providing a device comprising one or more sensors disposed thereon; generating a magnetic field with the antenna array of the probe; detecting a signal induced in the one or more sensors; determining a location and / or orientation of the one or more sensors; and guiding the device to a target tissue based on the location and / or orientation.

[0055] In another aspect, a method for guiding a device within a patient is provided, comprising: inserting a probe comprising an antenna array into the patient; providing a device comprising one or more magnetic field generators disposed thereon; generating a magnetic field at the location of the magnetic field generators on the device; measuring magnetic fields induced into each element of the antennae array; determining a location and / or orientation of - 9 - SG Docket No.: 14676-705.600the one or more magnetic field generators; and guiding the device to a target tissue based on the location and / or orientation.

[0056] In some aspects, the method includes delivering a therapeutic agent comprising vapor, a pharmacological agent, and / or a structural agent to a target tissue.

[0057] In one aspect, the probe is a transurethral ultrasound (TRUS) probe.

[0058] In some aspects, determining the location and / or orientation of the tip-mounted transducer is within a localized tracking volume.

[0059] In other aspects, the localized tracking volume is less than 200 cubic centimeters.

[0060] In some aspects, guiding the device further comprises maintaining motioninvariant tracking.

[0061] In other aspects, the method includes capturing an image.

[0062] In some aspects, the method includes combining a magnetic resonance imaging (MRI) image with the image captured by the probe.

[0063] In one aspect, the device is a needle.

[0064] In another aspect, guiding comprises deploying the needle to one or more locations in or near the target tissue.

[0065] In some aspects, the probe and device move together with the patient to eliminate the need for re-registration.

[0066] In one aspect, the method further comprises deploying the needle with one or more overlapping ablation points to cover a target zone.

[0067] In one aspect, the method further comprises stepwise rotation of a shaft of the needle with virtual needle deployment to determine optimal placement.

[0068] In another aspect, the method further comprises animating a real-time display of the shaft and needle tip on a console.

[0069] In one aspect, the method further comprises tracking needle deformation in tissue

[0070] In some aspects, the method further comprises using a plurality of sensors in the probe to increase tracking accuracy.

[0071] In one aspect, the method further comprises capturing real-time visualization of delivered vapor.

[0072] In another aspect, the needle is configured for delivery of vapor, a drug, and / or an adhesive.BRIEF DESCRIPTION OF THE DRAWINGS

[0073] A better understanding of the features and advantages of the methods and apparatuses described herein will be obtained by reference to the following detailed- 10 - SG Docket No.: 14676-705.600description that sets forth illustrative embodiments, and the accompanying drawings of which:

[0074] FIG. 1 provides an exemplary system diagram of an ultrasound-guided vapor delivery system comprising an external electromagnetic field generator, a transrectal ultrasound (TRUS) probe, and a vapor delivery device having a needle tip with electromagnetic tracking coils and vapor delivery openings.

[0075] FIG. 2 provides representative transverse and sagittal transrectal ultrasound (TRUS) images of a prostate during a vapor ablation procedure, including overlays of a tracked vapor delivery device, a projected needle trajectory, and a target treatment region derived from preoperative imaging.

[0076] FIG. 3 provides an exemplary ultrasound-guided vapor ablation system including a transrectal ultrasound (TRUS) probe having integrated tracking antennae and a vapor delivery device positioned within a patient’s urethra and prostate.

[0077] FIG. 4 provides an exemplary multi-coil sensor array arranged on a cube, including rectangular coils, coil leads, and associated magnetic field and magnetic field gradient components used to determine the position and orientation of a tracked transmitter.

[0078] FIGS. 5A-5C provide exemplary probe configurations of transmitter and sensor elements.

[0079] FIGS. 6A-6B provides exemplary TRUS probes with different sagittal and axial array configurations.

[0080] FIG. 7 provides an exemplary endoscopic ultrasound procedure with an integrated tracking cube in the endoscope and a tip-mounted coil on a surgical or biopsy tool for realtime device localizationDETAILED DESCRIPTION

[0081] Conventional systems for transrectal ultrasound (TRUS)-guided vapor ablation procedures typically employ electromagnetic (EM) tracking architectures in which a field generator antenna array is positioned external to the patient and configured to generate magnetic fields for localization of sensors mounted on an interventional device and, in some cases, on the ultrasound probe. While such systems can provide spatial tracking of a vapor delivery needle relative to an ultrasound image, they present several drawbacks in practice. For example, the external field generator is often bulky and occupies valuable space in the clinical environment, requiring setup, calibration, and ongoing adjustment during a procedure. In addition, the accuracy of tracking may be degraded by interference from nearby conductive or magnetically permeable materials, which can distort the generated fields - 11 - SG Docket No.: 14676-705.600through eddy currents or magnetic coupling. These systems may also require additional sensors to track the position of the TRUS probe itself, as well as re-registration when patient or equipment movement occurs relative to the fixed field generator. As a result, conventional EM tracking approaches can introduce complexity, workflow inefficiencies, and potential inaccuracies in image-guided vapor ablation procedures.

[0082] FIG. 1 provides an example of atransrectal ultrasound (TRUS) image-guided vapor ablation system 100 configured for treatment of prostate tissue. The system includes a system console 102 operatively coupled to a field generator antenna array 104, a TRUS probe 106, and a vapor delivery device 108. The field generator antenna array is configured to generate electromagnetic fields used for tracking the position of one or more sensors associated with the vapor delivery device.

[0083] The vapor delivery device includes a delivery device shaft 110 extending to a deployable vapor delivery needle 112. The needle comprises one or more vapor delivery openings 114 configured to emit vapor into surrounding tissue and at least one needle tip coil 116 configured as an electromagnetic tracking sensor. In some embodiments, the needle tip coil 116 may be wound around a recessed outer diameter of the needle tip or alternatively wound around a permeable core positioned within a channel formed in a wall of the needle. In addition, one or more shaft-mounted sensors 118 may be disposed along the delivery device shaft to facilitate tracking of the orientation and position of the vapor delivery device.

[0084] The TRUS probe 106 also includes one or more TRUS sensor(s) 107 configured to sense the magnetic field from the field generator array.

[0085] The field generator array 104 that contains a plurality of antennae that are energized with AC current to provide an alternating magnetic field throughout the space around the antennae. The magnetic field is sensed by sensors in the vicinity, including needle tip coil 116, shaft-mounted sensors 118, and TRUS sensor(s) 107. The field generator antennae are energized sequentially or simultaneously at distinct frequencies. Mathematical equations or empirical maps of the magnetic field surrounding each antenna are inverted to determine the 3D location and orientation of each sensor relative to the field generator box.

[0086] Since the TRUS probe is rigid, the location of the ultrasound imaging crystals is determined by translation from the location of the sensor 107 on the TRUS probe. The system console is configured to receive signals from sensors to determine the spatial position of the needle tip, TRUS probe, and shaft relative to the field generator array. The TRUS probe includes an ultrasound imaging array configured to generate real-time ultrasound images of a target region, such as the prostate. The location of sensors on the needle tip (e.g., needle tip coil 116) and the location of the shaft-mounted sensors 118 are then determined - 12 - SG Docket No.: 14676-705.600relative to ultrasound crystal locations by subtraction of Cartesian components. A marker of the location of the sensors can be placed on the real time TRUS image to show the location of devices in real time as they are moved through the anatomy.

[0087] In operation, the field generator antenna array 104 produces electromagnetic fields that are detected by the needle tip coil 116 and shaft-mounted sensors 118. Based on these detected signals, the system console computes the location of the vapor delivery device and displays the position of the needle tip relative to the ultrasound image. However, the use of the external field generator antenna array may introduce limitations, including sensitivity to interference from nearby conductive or magnetically permeable materials, the need for additional sensors to track the position of the TRUS probe, and the requirement for system setup and calibration. Additionally, tracking accuracy may be affected when components move outside a defined tracking volume.

[0088] The TRUS probe is inserted into the patient’s rectum and generates real time images of the prostate in two orthogonal planes, as seen in FIG. 2. The goal of the procedure is to identify the location of a tumor found on a preoperative MRI scan, identify the tip of the vapor delivery needle using an electromagnetic tracking system, and guide the needle tip to the proximity of the cancer to deliver vapor that ablates the tumor.

[0089] When sensors are at a known location on rigid device components, an animation of the component may be superimposed on the TRUS image. For example, the delivery device shaft is animated onto the TRUS image in FIG. 2, given the known locations of the probe tip sensors relative to the shaft. The needle tip advances in a preferred arc in air or tissue models, and this arc is shown in FIG. 2 relative to the shaft tip. However, the needle may deform as it traverses prostate tissue, so it is important to track the needle tip to know the precise location of the vapor delivery holes. Ultrasound images with sensor location markers and animated devices are displayed to the user on the system console and / or on one or more monitors attached to the console.

[0090] TRUS images taken from a vapor ablation procedure are shown in FIG. 2, along with an animation of the vapor delivery device shaft and an animation of the estimated extent between the first and last vapor delivery holes. An animation of cancerous tissue taken from a preoperative MRI is superimposed onto the TRUS image. In practice, the delivery device shaft is advanced to the transverse plane containing the tumor. An animation of the needle extending from the animated shaft is shown as the shaft is rotated until the needle animation is at a desired location relative to the tumor animation. The needle is then delivered from the shaft tip and advanced until the needle vapor delivery holes are at a desired location where- 13 - SG Docket No.: 14676-705.600vapor is delivered. Vapor is visible on the ultrasound image, so the extent of ablation may be estimated and displayed on new TRUS images.

[0091] The Field Generator Antennae Array box shown in FIG. 1 is bulky, can get in the way of therapy equipment, often needs to be adjusted when the patient or sensors move out of its tracking range, gives distorted fields at sensor locations (and tracking errors) when a conductive material is near the box (due to eddy currents generated in these materials by the box’s AC magnetic fields), gives distorted fields at sensor locations when magnetically permeable materials are near the box, requires an extra sensor to track the location of the TRUS crystal arrays, requires set-up and maintenance, adds to system inventory that needs calibration, and is generally a nuisance.

[0092] This disclosure provides improved systems and methods that integrate the field generator tracking array of FIG. 1 into the TRUS probe. Since magnetic field strength generally falls off with the cube of the separation from its source, the necessary volume of the antennae array and antennae driving power can be greatly reduced when the antennae are close to the tracking sensors. For example, in the prostate vapor ablation application, the vapor delivery needle tip will lie within ten cm separation from the TRUS probe.

[0093] FIG. 3 provides a system with electromagnetic tracking array 309 incorporated directly into the body of the TRUS probe 306 rather than being housed in a separate external box. The internalized array may be positioned near the transverse and sagittal ultrasound crystal arrays 320 and 322 within the probe nose cone 324 or along other structural elements of the probe, ensuring close proximity to the tracked needle tip and shaft of the vapor delivery device. Integrating the tracking array into the probe reduces the physical footprint of the system, eliminating the need for large external field generators that occupy space in the procedure room. The internalized design simplifies setup, minimizes interference with other equipment, and reduces the number of steps required for calibration.

[0094] The internalized array 309 may include one or more coils or cubes with precisely arranged windings, capable of sensing or transmitting magnetic fields in multiple orthogonal axes. This design enables high-fidelity detection of the device tip position and orientation within the patient. By being part of the probe, the array moves with the patient and imaging device, providing inherently motion-stable tracking.

[0095] By transmitting directly from the TRUS probe, the location of the needle tip and / or needle shaft can be detected in real time with high precision. As discussed above, one or both of the needle and shaft may include sensors or coils, allowing the system to determine both the orientation and the insertion trajectory of the needle. The transmitted signal can operate at distinct frequencies to avoid interference between multiple coils or with other - 14 - SG Docket No.: 14676-705.600system electronics. In embodiments with multiple needles or delivery devices, each needle can be uniquely identified by its transmitter frequency or phase. This architecture supports advanced features such as animated needle superimposition on TRUS images and virtual deployment planning, as described in FIG. 2, improving the clinician’s ability to accurately deliver therapy to the target tissue.

[0096] Another aspect of the disclosure provided herein is the application of low-power internal tracking volume. Because the tracking volume is confined to the patient’s anatomy, transmit power requirements are significantly reduced compared to conventional external tracking systems. Transmit power levels below 0.1 W are sufficient to generate detectable signals at the internalized TRUS antennae array. Low-power operation reduces the risk of tissue heating and minimizes interference with nearby electronics, making the system safer and more reliable in a clinical environment. Even with low power, precise tracking is maintained due to the proximity of the needle-transmitter to the probe-mounted sensors. Magnetic field strength falls off with the cube of the distance from the source, so reducing the separation between needle and probe increases signal strength and positional accuracy. This low-power approach also allows continuous real-time tracking during needle insertion and therapy delivery without excessive energy consumption or overheating of probe electronics.

[0097] Another aspect of the disclosure provided herein is restriction of localized tracking volume. By restricting the tracking volume to approximately 200 cubic centimeters, entirely contained within the patient, the system avoids interference from external metallic objects such as carts, monitors, or nearby medical equipment. This small, patient-centered volume contrasts sharply with conventional systems that generate tracking fields over tens of thousands of cubic centimeters, making them susceptible to distortion by eddy currents in nearby conductive materials.

[0098] Localized tracking ensures that sensor readings are stable and accurate, even in crowded procedure rooms. It also allows the use of simpler mathematical algorithms to calculate the 3D position and orientation of the needle tip, improving computational efficiency. FIG. 1 illustrates the conventional limitations that this localized internal system addresses, while FIG. 3 demonstrates the integrated TRUS probe with cubes and needle tip coils fully contained within the patient’s anatomy.

[0099] One aspect of the disclosure provided herein is a motion-invariant tracking system. In this system, the TRUS probe and the tracked interventional devices, such as the vapor delivery needle and delivery shaft, move together with the patient. Because the imaging and tracking components are physically linked to the patient, any motion, voluntary or involuntary, does not require re-registration of the tracking system. The sensor readings - 15 - SG Docket No.: 14676-705.600remain accurate, and the needle tip position is continuously updated in real time relative to the prostate anatomy as shown in FIG. 2.

[0100] This design improves procedural efficiency and accuracy, reducing potential errors caused by patient movement. It also minimizes the need for additional sensors or manual adjustments during the intervention, creating a more seamless workflow for the clinician. The real-time TRUS images displayed on the system console reflect the precise positions of the needle and shaft as they move with the patient, ensuring reliable guidance throughout the procedure.

[0101] Another aspect of the disclosure provided herein is the combination of integrated electromagnetic tracking with vapor ablation therapy. The tracked needle delivers condensable vapor directly into the targeted prostate tissue, enabling controlled thermal ablation of cancerous regions. Real-time TRUS imaging, augmented by the tracking system, allows the clinician to localize the needle tip and visualize the spread of vapor within the prostate as depicted in FIGS. 2 and 3.

[0102] By overlaying an animated representation of the delivery device and the expected vapor distribution on the TRUS images, the clinician can accurately determine when and where to deliver each dose. This precise guidance protects surrounding structures, such as the prostatic urethra and neurovascular bundles, while achieving complete ablation of the tumor tissue. The system supports multiple treatment points with overlapping vapor doses to ensure comprehensive coverage of the target zone.

[0103] One aspect of the disclosure provided herein is the integration of pre-operative MRI with real-time TRUS imaging. MRI scans are used to identify the precise location and boundaries of prostate tumors. These images are then fused with TRUS images displayed during the procedure, providing a multi-modal guidance system for needle placement and vapor deliver as shown in FIG. 2.

[0104] The fusion allows clinicians to see both the anatomical context from MRI and the real-time movement from TRUS, improving targeting accuracy. Tumor regions identified on MRI can be overlaid on the TRUS display, along with the animated needle trajectory and estimated vapor ablation zone. This combination facilitates careful planning and execution of ablation procedures, minimizing damage to non-target tissue and optimizing therapeutic outcomes.

[0105] FIG. 2 shows an animated TRUS screen capture during a vapor ablation procedure targeting, before the vapor needle has been deployed. The transverse image plane includes an estimated zone of prostate cancer as seen in pre-operative MRI scans. Any points in or near the zone outlined in red are targets for vapor delivery. Vapor may be delivered at multiple - 16 - SG Docket No.: 14676-705.600points with overlapping treatments covering the red zone and in a margin around the zone. The delivery device shaft is animated in both the transverse and sagittal images of these conventional TRUS images. Note that target tissue distal of the transverse plane does not show up in the sagittal view. The arrow in the transverse animation of the shaft indicates the direction that the needle will deploy. The two green lines in the transverse image represent the estimated start and end of the vapor delivery holes. The pink line shows the furthest point that the needle could reach if it were fully deployed. The orange line in the transverse view indicates the sagittal plane, while the blue line in the sagittal view indicates the transverse plane. Note that the needle will not intersect the transverse plane except when it leaves the shaft and cannot be guided to this location by TRUS imaging alone. In general, it is often difficult or impossible to locate the needle tip in the TRUS images without a tracking system. The user may deploy the needle and delivery vapor at this location or continue to rotate the shaft and virtually deploy the needle until he determines the best place for vapor delivery.

[0106] In some embodiments, the transverse and sagittal TRUS image planes are displayed simultaneously on a system console and are spatially registered such that a position in one plane corresponds to a known position in the other plane. Visual indicators may be provided to represent the relative location and orientation of each imaging plane, including lines or markers overlaid on each image to indicate the position of the orthogonal plane. This dual-plane visualization assists the user in understanding the three-dimensional spatial relationship between the vapor delivery device and the target tissue.

[0107] The system may be configured to generate and display graphical overlays corresponding to one or more components of the vapor delivery device based on electromagnetic tracking data. Such overlays may include, without limitation, a representation of the delivery device shaft, a projected needle trajectory, an estimated deployed needle position, and one or more indicators corresponding to vapor delivery openings. In some embodiments, the projected needle trajectory is calculated based on a known mechanical relationship between the needle and the shaft and may be updated in real time as the shaft is translated or rotated.

[0108] In some embodiments, image data from a preoperative imaging modality, such as magnetic resonance imaging (MRI), is registered to the TRUS images and displayed as an overlay. The registered image data may include a segmented region corresponding to cancerous or suspected cancerous tissue. The system may be configured to align the MRI-derived data set with the TRUS coordinate system using rigid or deformable registration techniques, thereby enabling the user to visualize target regions that may not be readily distinguishable in ultrasound imaging alone. The system may further be configured to display - 17 - SG Docket No.: 14676-705.600an estimated treatment region corresponding to vapor delivered from the needle. For example, based on the location of vapor delivery openings and one or more treatment parameters, such as delivered energy or duration, an estimated ablation volume may be computed and displayed on the TRUS image. In some embodiments, multiple treatment regions may be visualized to represent overlapping vapor deliveries intended to cover a target region and a surrounding margin.

[0109] Because the needle may deflect or deform as it advances through tissue, the actual position of the needle tip and associated vapor delivery openings may deviate from a predicted trajectory. Accordingly, electromagnetic tracking of the needle tip provides improved accuracy in determining the location of vapor delivery relative to the target tissue. The tracked position of the needle tip may be continuously updated and displayed on the TRUS images, thereby enabling the user to adjust the position and orientation of the delivery device during the procedure.

[0110] In some embodiments, the system provides interactive controls that allow a user to manipulate the displayed overlays, including rotating a virtual representation of the delivery device, previewing a projected needle deployment, and selecting target locations for vapor delivery. The user may iteratively adjust the position and orientation of the delivery device shaft while observing the projected needle trajectory relative to the target region prior to actual needle deployment.

[0111] One aspect of the disclosure provided herein is a multimodal needle delivery system. The needle system is configured to deliver not only condensable vapor for tissue ablation, but also pharmacological agents such as antibiotics, chemotherapeutics, or toxins, as well as structural agents like adhesives or sealants. The integrated tracking system ensures that all agents are delivered precisely to the target site within the prostate under real-time TRUS guidance.

[0112] The previously described concepts of low-power internal tracking are applied here in a practical anatomical embodiment. Tracking coils are positioned at the needle tip and shaft tip, while the TRUS probe contains integrated tracking array in the nose cone. This arrangement enables continuous, accurate localization of the needle within the prostate, even as the patient moves, supporting the precise delivery of vapor or other agents. Additionally, the motion-invariant tracking concept applies herein. Because the TRUS probe and needle move together with the patient, the system maintains accurate registration without requiring re-calibration, ensuring safe and reliable guidance throughout the procedure. FIG. 3 illustrates the integration of combination with vapor ablation therapy. The needle tip is guided to the target tissue identified via MRI-TRUS fusion, allowing vapor to be delivered with precision,- 18 - SG Docket No.: 14676-705.600while minimizing exposure to surrounding healthy structures. The anatomical depiction emphasizes how multimodal delivery is made possible by the integrated tracking system.

[0113] One embodiment of this disclosure is shown in FIG. 3. A TRUS probe comprising transverse 320 and sagittal 322 imaging arrays has a tracking array 309 mounted in the probe nose cone. The TRUS probe is shown inserted into the patient’s rectum. The vapor delivery device shaft 310 is shown in the patient’s urethra with the vapor delivery needle 312 extending from the shaft tip into the prostate. Two shaft-mounted sensors 318 are shown near the shaft tip and one needle tip sensor 316 is placed near the needle tip. The sensors may comprise coils of fine wire that generate an AC voltage induced in the windings by an AC current flowing in the tracking array 309 of the TRUS probe 306. Some antennae or sensor coils may include permeable materials proximate to their windings to enhance a magnetic field.

[0114] In some embodiments the coils on the delivery device shaft and needle tip are transmitter coils while the cube coils or array on the TRUS probe are sensor coils. In some embodiments, the tracking arrays are arranged on one or more geometric support structures, including a cube, to provide spatially distributed sensing of electromagnetic signals. The arrays are positioned so as not to interfere with operation of the ultrasound imaging arrays.

[0115] In some embodiments, the coils disposed on the vapor delivery device are configured as transmitters that emit electromagnetic signals, while the antennae integrated within the TRUS probe function as receivers that detect the emitted signals. In other embodiments, the roles of the coils may be reversed, or the coils may alternate between transmitting and receiving modes. Because the antennae are located in close proximity to the needle tip coil during use, the system may operate with reduced transmit power while maintaining sufficient signal strength for accurate tracking.

[0116] The integration of the tracking antennae within the TRUS probe enables determination of the position of the shaft tip and needle directly relative to the ultrasound imaging arrays. This configuration may eliminate the need for external field generator components and additional probe-mounted sensors and may reduce susceptibility to interference from external conductive or magnetically permeable objects. Furthermore, as both the TRUS probe and vapor delivery device are positioned within or relative to the patient anatomy, tracking accuracy may be maintained despite patient movement.

[0117] One aspect of the disclosure provided herein is the use of theoretically exact mathematical formulas to determine the precise location and orientation of a transmit coil relative to a sensor cube. A plurality of rectangular sensor coils are mounted on the faces of the cube, and voltages induced by the magnetic fields of device-mounted transmit coils are - 19 - SG Docket No.: 14676-705.600measured. These voltage measurements are then fit to the analytic formulas using a least squares method. By adjusting the assumed position and orientation of the transmit coil to minimize the error between measured and calculated voltages, the system can resolve the transmit coil’s three-dimensional Cartesian coordinates and orientation angles with high accuracy.

[0118] In another embodiment, the least squares fitting can be applied continuously during a procedure, allowing real-time tracking of the needle tip or shaft tip. This ensures that even small deviations in the position or orientation of the tracked device are detected, enabling precise alignment with target tissue. The use of a plurality of sensor coils enhances the robustness of the fitting algorithm, as redundant measurements improve noise rejection and accuracy.

[0119] Furthermore, the method is compatible with multiple transmitters operating at distinct frequencies or in sequence. The mathematical framework allows the system to simultaneously track several coils on different interventional tools without loss of precision. This approach provides a foundation for accurate, real-time, multi-device tracking integrated with ultrasound imaging.

[0120] Another aspect of the disclosure is the use of gradient tensor sensing to enhance localization accuracy. A plurality of sensor coils on the cube measure not only the local magnetic field vectors but also selected components of the magnetic field gradient tensor. By capturing both field and gradient data, the system can analytically determine the transmit coil’s location and orientation without complex initialization procedures.

[0121] In practice, gradient tensor sensing provides additional spatial information that is particularly valuable when the tracking environment contains minor distortions or the transmit coil is near boundaries of the sensor array. Using a plurality of coils to measure gradients in multiple directions ensures that sufficient independent data points are available for exact analytical solutions. The combination of field and gradient measurements reduces ambiguity and improves tracking reliability, even in confined anatomical spaces such as the prostate.

[0122] One example of an array of twelve rectangular coils mounted on a cube having side “a” that may be a = 1.2 cm and may be a < 2 cm is shown in FIG. 4. The rectangular coils may be free-standing coils with leads shown. The coils are mounted on a sculpted cube having printed or etched groves that capture the free-standing coils. The groves and coils may be constructed with sub-mil accuracy using modem coil winding and printing technologies. In one embodiment the twelve coils are sensors and the voltages induced in the coils by AC magnetic fields generated by currents flowing sequentially (or at different - 20 - SG Docket No.: 14676-705.600frequencies) in shaft and needle tip transmitter coils. One preferred technique to compute the transmit coil vector location and orientation relative to the cube center involves matrix inversion of tensors that employ measurements of the sensor magnetic fields and field gradients. Components of the magnetic field vector and field gradient tensor are given in FIG. 4. Vij are the measured voltages induced in each of the 12 rectangular coils times a calibration factor that converts the voltage to a magnetic field.

[0123] In the embodiment shown in FIG. 4, the plurality of rectangular coils are arranged on multiple faces of the cube such that each coil occupies a defined orientation relative to a Cartesian coordinate system centered at the cube. The coils may be positioned to measure independent components of the magnetic field vector and spatial gradients of the magnetic field generated by a transmit coil located on an interventional device. In some embodiments, pairs of coils disposed on opposing faces of the cube may be configured to generate differential signals corresponding to magnetic field gradients along respective axes.

[0124] The measured voltages from the plurality of coils may be combined to determine components of the magnetic field vector (Bx, By, Bz) and components of the magnetic field gradient tensor (e.g., dBx / Sx, c x / fy, 3Bx / &, etc.). These components may be expressed as functions of the measured coil voltages Vij and corresponding calibration factors. In some embodiments, the number and arrangement of coils are selected such that a sufficient number of independent measurements are obtained to solve for the three-dimensional position and orientation of a magnetic dipole transmitter relative to the cube.

[0125] In one preferred embodiment, the magnetic field and gradient measurements are used in a system of equations that may be solved to determine the spatial coordinates and angular orientation of the transmit coil. The solution may be obtained using matrix inversion, least-squares fitting, or closed-form analytical expressions, depending on the specific arrangement and number of coils. In certain embodiments, the availability of both field and gradient information enables direct analytical inversion of the governing equations without requiring iterative initialization, thereby improving computational efficiency and robustness.

[0126] The use of a compact cube geometry with closely spaced coils enables accurate sensing of magnetic field variations over a small spatial region, which is particularly suited for tracking applications in confined anatomical volumes. Because the separation between the transmit coil and the sensor array is relatively small during use, the measured signals may exhibit high signal -to-noise ratios even at low transmit power levels. This configuration may reduce susceptibility to external interference and enable precise tracking of the interventional device within the target anatomy.- 21 - SG Docket No.: 14676-705.600

[0127] In some embodiments, the coils may be formed using fine conductive wire, printed conductive traces, or other micro-fabrication techniques, and may be integrated into a support structure that maintains precise geometric relationships between the coils. The support structure, such as the cube shown in FIG. 4, may be incorporated into a medical probe, including a transrectal ultrasound probe, such that the coil array is fixed relative to an imaging array. Electrical leads from the coils may be routed through the probe body to a processing system configured to compute the position and orientation of a tracked device in real time.

[0128] One aspect of the disclosure provided herein is the use of gradient tensor sensing with a plurality of sensor coils to determine the precise position and orientation of transmitters mounted on interventional devices. In this embodiment, multiple sensor coils are placed on one or more cubes within the ultrasound probe. By measuring the magnetic field vectors and selected gradient components at each coil, the system can compute an exact analytical solution for the transmit coil’s 3D location and orientation.

[0129] Using a plurality of coils provides redundancy and enhances robustness, allowing the tracking system to compensate for small distortions, coil misalignments, or minor magnetic interference within the confined anatomical space. Multiple cubes, located both proximal and distal to the ultrasound crystals, provide a baseline that increases accuracy across the entire tracking volume. This baseline is especially valuable for procedures where the device tip must be precisely located relative to the imaging plane.

[0130] Another embodiment involves continuously updating the gradient tensor measurements in real-time as the tracked device moves. The plurality of coils allows simultaneous measurement of multiple field components and gradients, enabling accurate motion tracking even when the device rotates, bends, or interacts with tissue. The analytical approach avoids iterative initialization, providing immediate and reliable tracking information.

[0131] Another aspect of the disclosure provided herein is the strategic placement of a plurality of coils on cubes within the TRUS probe and on the device shaft or needle tip. These coils may function as sensors, transmitters, or both, and their positions are carefully chosen to maximize coverage and minimize ambiguity in tracking. The multiple coils on a cube can capture three orthogonal field components, while additional coils measure field gradients.

[0132] By using a plurality of coils in both the probe and device, the system can simultaneously track multiple points on a device, such as the shaft tip and needle tip. This configuration allows real-time animation of the device relative to the target anatomy, improving safety and treatment precision. The flexibility of the design allows the coils to be - 22 - SG Docket No.: 14676-705.600configured in cubes, integrated into probe walls, or otherwise distributed in the probe nosecone without interfering with ultrasound imaging.

[0133] One aspect of the disclosure provided herein is the use of a small spherical permanent magnet mounted within a cube in the ultrasound probe. The magnet may be rotated using orthogonal coil windings to generate a time-varying magnetic field. Because the magnetic moment of the magnet is orders of magnitude larger than that generated by currents in simple coils, it enables accurate detection by the shaft or needle-mounted sensors even at low transmit power (<0.1 W).

[0134] The use of a plurality of coils in the cube allows the system to detect the rotating magnet’s orientation in multiple axes. Real-time measurements of the magnetic field vectors induced in the sensor coils provide highly precise localization and orientation data. The magnet’s small size (<3 mm, or in some embodiments <2 mm) allows it to fit within the probe without increasing the overall probe dimensions.

[0135] The internalized antenna array and low-power internal tracking volume concepts apply here. The placement of multiple cubes with a plurality of coils within the probe maintains the benefits of compact, patient-centered tracking while enabling high-accuracy gradient tensor sensing and magnet-based transmitter detection.

[0136] Transmitter and sensor configurations for the integrated tracking system are shown in FIGS. 5A-5C. Sensors / transmitters may be placed anywhere on the delivery device shaft. In a preferred embodiment shown in FIG. 5A, one or more orthogonal coils 518 / 519 are placed in the shaft or shaft tip to track the shaft / tip in three dimensions using a minimum number of coils within TRUS probe. A needle tip coil 512 may also be provided. Any of the coils discussed herein can be a sensor or transmitter. In a preferred embodiment, a set of three orthogonal coils is positioned near the shaft tip to enable determination of position and orientation of the shaft tip in three-dimensional space. A needle tip coil may be positioned distal to the shaft tip coils and may provide additional tracking accuracy for the distal end of the device, particularly in applications where the needle may deviate from a predicted trajectory. In some embodiments, signals from both shaft tip coils and needle tip coils are combined to improve estimation of device geometry within tissue.

[0137] In FIG. 5B, One or more tracking cubes or arrays 509 may be placed within the TRUS probe at select locations, typically in the nosecone distal to the sagittal array 522 and transverse array 520. The cubes may comprise 3 - 12 coils that may be sensors, transmitters or both.

[0138] One embodiment, shown in FIG. 5C, shows a spherical magnet 526 that resides in a spherical cavity within magnet rotation coils 528 mounted in the TRUS probe nose cone.- 23 - SG Docket No.: 14676-705.600The cube can include two orthogonal windings for rotating the magnet about a single axis, or three orthogonal coils for rotating the magnet about an arbitrary axis. Gradient coils may be provided for both levitation and rotation of the magnet. A neodymium-iron-boron or ironnitride permanent magnet has a magnetic moment that is orders of magnitude larger than a moment created by current flowing in a cube coil. A spherical magnet having diameter < 3 mm or a diameter < 2 mm can project magnetic fields that are large compared to current flowing in a simple cube coil. A small spherical magnet can rotate at speeds up to 4,000 cycles / second, generating sufficiently large voltages in shaft or needle mounted sensors for accurate tracking.

[0139] The rotating permanent magnet may generate a time-varying magnetic field that can be detected by one or more sensors located on the delivery device, such as coils or magnetic field sensors positioned along the shaft or at the needle tip. Due to the relatively large magnetic moment of materials such as neodymium-iron-boron or iron-nitride, the magnetic field generated by a small magnet may be significantly greater than that produced by a comparably sized current-driven coil. As a result, strong detectable signals may be generated even with compact magnet sizes, such as diameters less than approximately 3 mm.

[0140] In some embodiments, the magnet may be rotated at a controlled frequency, which may be constant or varied over time, to produce distinguishable magnetic field components that can be used to determine position and orientation of the delivery device. The rotation may occur at frequencies sufficient to induce measurable signals in the sensors, for example up to several thousand cycles per second. The use of a rotating magnet may reduce power consumption and simplify transmitter design while maintaining or improving tracking performance.

[0141] The TRUS probe of FIGS. 5B-5C may include one or more arrays of coils or sensors positioned relative to ultrasound imaging arrays, such as sagittal and transverse arrays 522 and 520. In some embodiments, the tracking coils are arranged on one or more geometric structures, including cubes, positioned within the probe, such as within a distal nose cone region or proximal to an imaging array. The number of coils in each structure may vary, for example between three and twelve coils, and the coils may be configured as transmitters, receivers, or both depending on the selected tracking architecture.

[0142] It will be appreciated that the various transmitter and sensor configurations described herein may be used individually or in combination. For example, a system may include both coil-based transmitters and a rotating magnet or may dynamically switch between different transmission modalities. Such flexibility enables optimization of tracking- 24 - SG Docket No.: 14676-705.600performance for different procedural conditions, anatomical regions, or device configurations.

[0143] One aspect of the disclosure provided herein is an improvement to ultrasound probe geometry in which the axial (transverse) imaging array is centered relative to the sagittal (longitudinal) array. In this configuration, the axial plane intersects the sagittal plane near the target tissue, providing simultaneous imaging in both planes and facilitating more accurate localization of interventional devices such as needles or catheters.

[0144] In a preferred embodiment, the sagittal array runs parallel to the longitudinal axis of the delivery device shaft, while the axial array encircles the shaft circumference and intersects the sagittal array to form a cross or “X” configuration. This bi-plane alignment ensures that the target tissue appears near the center of both imaging planes, allowing the user to see the full extent of a tumor or lesion and accurately guide the needle tip to the desired location.

[0145] Another aspect of the disclosure provided herein is the use of multiple sagittal arrays arranged circumferentially around the shaft. This arrangement provides additional coverage and reduces blind spots during needle insertion or device navigation. The axial array at the tip of the probe complements these arrays, allowing precise visualization of tissue structures at varying depths while maintaining the intersection with sagittal planes.

[0146] The centered axial-sagittal design also supports integration with the internalized tracking system introduced in FIG. 1. By aligning the imaging planes with the tracking sensors and transmitters, the system can overlay real-time device positions onto both planes, enhancing guidance for procedures such as vapor ablation, biopsies, or multi-modal delivery. As previously described for FIG. 1, the internalized antenna array and low-power tracking volume concepts are compatible with the advanced ultrasound geometry. The probe’s crossed arrays allow simultaneous imaging and tracking within a confined anatomical volume, improving accuracy, procedural efficiency, and patient safety without increasing system complexity.

[0147] FIGS. 6A-6B illustrate examples of TRUS probe configurations that enable crossed-plane imaging of the prostate. In the embodiment of FIG. 6 A, a single sagittal array 622 is aligned parallel to the longitudinal axis of the delivery device shaft, while the transverse array 620 is arranged around the circumference of the shaft and intersects the sagittal array, forming a cross or X pattern. This configuration allows the intersection point of the arrays to be positioned directly over the targeted tissue, so that both sagittal and transverse images are centered on the tumor region or target tissue.- 25 - SG Docket No.: 14676-705.600

[0148] In another embodiment shown in FIG. 6B, multiple sagittal arrays 622 are distributed around the circumference of the shaft, each parallel to the longitudinal axis, with a separate transverse array 620 positioned at the distal tip of the probe. This arrangement allows for broader coverage and flexibility in locating the target tissue in three dimensions while maintaining high-resolution imaging in both the transverse and sagittal planes. The transverse array at the tip ensures that vapor delivery zones are fully visualized, even for tumors located at varying depths within the prostate.

[0149] The crossed-plane TRUS geometries shown in FIGS. 6A-6B provide improved guidance for needle placement and vapor delivery compared to conventional TRUS systems. By centering both imaging planes on the target tissue, the physician can more accurately monitor needle tip position, estimate the extent of tissue ablation, and reduce the risk of incomplete or off-target treatments. This design is compatible with electromagnetic tracking sensors or coils integrated into the needle and shaft, enabling real-time visualization of both the delivery device and the targeted tissue within the crossed-plane TRUS images.

[0150] Although described here in the context of transrectal prostate procedures, the crossed-plane TRUS probe configurations of FIGS. 6A-6B may also be applied to other ultrasound-guided interventions, including transvaginal, endoscopic, intravascular, or interventional cardiac ultrasound procedures, providing enhanced guidance for tissue ablation, fluid delivery, or biopsy in multiple anatomical regions.

[0151] The TRUS images shown in FIG. 2 were taken with a conventional TRUS in which the transverse (axial) imaging plane is placed at the end of the sagittal imaging plane. For vapor therapy the needle is located relative to the targeted tumor tissue in the axial plane, so that tissue is seen in the sagittal image that is generally on the proximal side of the tissue ablation. The improved TRUS seen in FIGS. 5A-5C and 6A-6B, in which the axial plane crosses the sagittal plane, may have both axial and sagittal images centered on the target tissue, and is therefore preferred for tumor targeting and vapor ablation. The crossed plane TRUS can be equally valuable in the other TRUS-guided procedures discussed below.

[0152] Ultrasound guided vapor ablation therapy with integrated device tracking is one of many procedures that will benefit from this disclosure. Any ultrasound guided procedure or intervention that can benefit from real time tracking of the location of a device wherein the device is separated by no more than 10 - 20 cm from the ultrasound imaging array is a candidate for this integrated tracking systems as described herein.

[0153] FIG. 7 shows a liver biopsy application where a tracking antennae array 709 has been added to an Endoscopic Ultrasound (EUS) catheter 701 having integrated ultrasound 703 and a sense / transmit coil 712 has been added to a biopsy tool 705 of the catheter 701.- 26 - SG Docket No.: 14676-705.600The location of the biopsy tool tip is superimposed on the real time ultrasound image in this application. Other biopsy applications and other ultrasound guided procedures may benefit from this disclosure. Some of these applications include: TRUS (Trans Rectal Ultrasound), which can include prostate tissue biopsy procedures, vapor ablation procedures, RF, microwave, waterjet, surgical ablation procedures, and / or External beam radiation marker placement; EUS (Endoscopic Ultrasound), which can include tissue biopsy of specific tissues (e.g., Liver, Esophagus, Pancreas, Colon), Tissue ablation, and / or Fiducial marker placement; ICE (Intra Cardiac Echo), which can include Tissue biopsy, Tissue ablation, Electrical mapping; Trans Vaginal Ultrasound, which can include Tissue biopsy (e.g., Ovaries, Uterus) or Tissue ablation; External Ultrasound, which can include Tissue biopsy and ablation of tissues (such as Breast, Thyroid, Lymph nodes), Drug or fluid injection, Cortisone injections, Indwelling drug delivery catheter placement, Paracentesis, Sub-xiphoid approach to pericardium (e.g., Electrical mapping, Tissue biopsy or ablation), and / or Carotid artery repair. It should be clear to anyone skilled in the art that the above list is limited and that this disclosure applies equally to other ultrasound guided procedures and interventions.

[0154] One aspect of the disclosure provided herein is the application of the integrated electromagnetic tracking system to various ultrasound-guided procedures beyond the prostate. By internalizing the antenna array within the imaging device and utilizing devicemounted transmitter or sensor coils, the system allows real-time tracking of instruments in anatomical regions where the target tissue lies within 10-20 cm of the imaging array.

[0155] This configuration supports procedures such as endoscopic ultrasound (EUS) guided biopsies or ablations, intra-cardiac echo (ICE) interventions, transvaginal ultrasound-guided therapy, and external ultrasound procedures including breast, thyroid, lymph node biopsies, drug delivery, or vascular access. The system maintains tracking accuracy without requiring external field generators, minimizing interference from surrounding metallic objects and eliminating the need for patient re-registration.

[0156] Another aspect of the disclosure provided herein is motion-invariant tracking, where both the imaging probe (e.g., endoscope or external transducer) and the tracked device move with the patient. This ensures that device localization remains accurate even if the patient or instruments shift during the procedure, reducing the likelihood of misplacement and enhancing procedural safety.

[0157] A further aspect of the disclosure is the combination of real-time ultrasound visualization with device tip localization for precise delivery of therapeutic or diagnostic interventions. In the embodiment shown in FIG. 7, a tracking antennae cube is embedded within an EUS catheter, and a coil is placed on the tip of a biopsy tool inserted into the liver.- 27 - SG Docket No.: 14676-705.600The position of the biopsy tool tip is superimposed on the real-time ultrasound image, allowing the operator to guide the device accurately to the target tissue.

[0158] In the example of FIG. 7, the EUS catheter is inserted into the gastrointestinal tract, with the tracking antenna cube embedded near the distal tip of the endoscope.Ultrasound crystals are positioned at the endoscope tip to provide real-time imaging of internal tissues, such as the stomach or liver. A surgical or biopsy tool is positioned within the liver, and a sensor or transmitter coil is located at the tip of the tool to enable electromagnetic tracking relative to the endoscope’s antennae cube.

[0159] The integrated tracking system allows the tip of the surgical or biopsy tool to be superimposed onto the real-time ultrasound image, providing accurate localization even when the tool is deep within tissue. The system is configured for a maximum separation of 10-20 cm between the ultrasound array and the tracked device, ensuring high signal fidelity without requiring bulky external field generators.

[0160] In some embodiments, multiple sensor or transmitter coils may be added along the shaft of the endoscope or the surgical tool to provide orientation and curvature information, enabling visualization of the tool trajectory through tissue. This allows the physician to plan and execute procedures with precision, including tissue biopsy, tumor ablation, fiducial marker placement, or fluid delivery.

[0161] Although FIG. 7 depicts a liver biopsy application, the system is equally applicable to a wide range of ultrasound-guided interventions, including tissue biopsy or ablation in the esophagus, pancreas, colon, or other organs. The use of integrated antennae and coils allows real-time tracking for virtually any endoscopic, intravascular, or externally guided ultrasound procedure where device location is critical.

[0162] By integrating the antennae cube into the endoscope, the disclosure eliminates the need for external field generators and reduces setup complexity, while providing high-accuracy tracking that is largely immune to interference from surrounding tissues or external metal objects. The result is improved procedural safety, efficiency, and visualization, particularly for interventions in anatomically complex regions.

[0163] It should be understood that the disclosure is not limited to liver biopsy applications. The same integrated tracking approach may be applied to other biopsy, ablation, or therapeutic procedures where the device tip is within a close range of the imaging array. By fusing real-time ultrasound with pre-operative imaging, the system enhances the accuracy, safety, and efficiency of minimally invasive procedures across multiple clinical contexts.

[0164] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not - 28 - SG Docket No.: 14676-705.600mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0165] The process parameters and sequence of steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed. The various example methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.

[0166] Any of the methods (including user interfaces) described herein may be implemented as software, hardware or firmware, and may be described as a non-transitory computer-readable storage medium storing a set of instructions capable of being executed by a processor (e.g., computer, tablet, smartphone, etc.), that when executed by the processor causes the processor to control perform any of the steps, including but not limited to: displaying, communicating with the user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), determining, alerting, or the like. For example, any of the methods described herein may be performed, at least in part, by an apparatus including one or more processors having a memory storing a non-transitory computer-readable storage medium storing a set of instructions for the processes(s) of the method.

[0167] While various embodiments have been described and / or illustrated herein in the context of fully functional computing systems, one or more of these example embodiments may be distributed as a program product in a variety of forms, regardless of the particular type of computer-readable media used to actually carry out the distribution. The embodiments disclosed herein may also be implemented using software modules that perform certain tasks. These software modules may include script, batch, or other executable files that may be stored on a computer-readable storage medium or in a computing system. In some embodiments, these software modules may configure a computing system to perform one or more of the example embodiments disclosed herein.

[0168] As described herein, the computing devices and systems described and / or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions, such as those contained within the modules described herein. In their most basic configuration, these computing device(s) may each comprise at least one memory device and at least one physical processor.

[0169] The term “memory” or “memory device,” as used herein, generally represents any type or form of volatile or non-volatile storage device or medium capable of storing data - 29 - SG Docket No.: 14676-705.600and / or computer-readable instructions. In one example, a memory device may store, load, and / or maintain one or more of the modules described herein. Examples of memory devices comprise, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory.

[0170] In addition, the term “processor” or “physical processor,” as used herein, generally refers to any type or form of hardware-implemented processing unit capable of interpreting and / or executing computer-readable instructions. In one example, a physical processor may access and / or modify one or more modules stored in the above-described memory device. Examples of physical processors comprise, without limitation, microprocessors, microcontrollers, Central Processing Units (CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor.

[0171] Although illustrated as separate elements, the method steps described and / or illustrated herein may represent portions of a single application. In addition, in some embodiments one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as the method step.

[0172] In addition, one or more of the devices described herein may transform data, physical devices, and / or representations of physical devices from one form to another.Additionally or alternatively, one or more of the modules recited herein may transform a processor, volatile memory, non-volatile memory, and / or any other portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and / or otherwise interacting with the computing device.

[0173] The term “computer-readable medium,” as used herein, generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media comprise, without limitation, transmission-type media, such as carrier waves, and non-transitory-type media, such as magnetic-storage media (e.g., hard disk drives, tape drives, and floppy disks), optical -storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media), and other distribution systems.- 30 - SG Docket No.: 14676-705.600

[0174] A person of ordinary skill in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequence of the steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed.

[0175] The various exemplary methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or comprise additional steps in addition to those disclosed. Further, a step of any method as disclosed herein can be combined with any one or more steps of any other method as disclosed herein.

[0176] The processor as described herein can be configured to perform one or more steps of any method disclosed herein. Alternatively or in combination, the processor can be configured to combine one or more steps of one or more methods as disclosed herein.

[0177] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element, or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected", "attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0178] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".- 31 - SG Docket No.: 14676-705.600

[0179] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly", "downwardly", "vertical", "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0180] Although the terms “first” and “second” may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another feature / element. Thus, a first feature / element discussed below could be termed a second feature / element, and similarly, a second feature / element discussed below could be termed a first feature / element without departing from the teachings of the present disclosure.

[0181] Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising” means various components can be co-jointly employed in the methods and articles (e.g., compositions and apparatuses including device and methods). For example, the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

[0182] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and / or steps may alternatively be exclusive and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components or sub-steps.

[0183] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and / or position to indicate that the value and / or position described is within a reasonable expected range of values and / or positions. For example, a numeric value may have a value that is + / - 0.1% of the stated value - 32 - SG Docket No.: 14676-705.600(or range of values), + / - 1% of the stated value (or range of values), + / - 2% of the stated value (or range of values), + / - 5% of the stated value (or range of values), + / - 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0184] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the disclosure as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the disclosure as it is set forth in the claims.

[0185] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have - 33 - SG Docket No.: 14676-705.600been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.- 34 - SG Docket No.: 14676-705.600

Claims

CLAIMS1. An integrated electromagnetic tracking system for guiding a device within a patient, comprising:an ultrasound imaging probe comprising a tracking antenna array configured to generate a magnetic field and one or more transducer arrays configured to generate ultrasound images of a target tissue;a transurethral vapor delivery device having a shaft and a vapor delivery needle deployable from the shaft, the vapor delivery device comprising one or more sensors disposed on the shaft and / or the vapor delivery needle configured to generate signals when in the presence of the magnetic field; anda system console configured to determine a position and / or an orientation of the shaft and / or the vapor delivery needle based on the signals.

2. An integrated electromagnetic tracking system for guiding a device within a patient, comprising:a transurethral vapor delivery device having a shaft and a vapor delivery needle deployable from the shaft, the vapor delivery device comprising one or more transmitters disposed on the shaft and / or the vapor delivery needle configured to generate a magnetic field;an ultrasound imaging probe comprising an antenna array configured to generate signals when in the presence of the magnetic field and one or more transducer arrays configured to generate ultrasound images of a target tissue; anda system console configured to determine a position and / or an orientation of the shaft and / or the vapor delivery needle based on the signals.

3. The system of any of the preceding claims, wherein the probe is a transrectal ultrasound (TRUS) probe.

4. The system of any of the preceding claims, wherein the tracking antenna array comprises a plurality of coils5. The system of any of the preceding claims, wherein the system console is configured to determine the location and / or orientation of the shaft and / or the vapor delivery needle in real-time.

6. The system of any of the preceding claims, wherein the probe and the device move with the patient to provide motion-invariant tracking.- 35 - SG Docket No.: 14676-705.6007. The system of any of the preceding claims, wherein the system console is configured to determine the location and / or orientation of shaft and / or the vapor delivery needle within a localized tracking volume.

8. The system of any of the preceding claims, wherein the localized tracking volume is less than or about 200 cubic centimeters.

9. The system of any of the preceding claims, wherein the localized tracking volume is tracked with a transmit power of less than 0.1 W.

10. The system of any of the preceding claims, wherein the tracking antenna array comprises a plurality of coils mounted on a cube, a spherical magnet, or gradient coils.

11. The system of any of the preceding claims, wherein the tracking antenna comprises a spherical magnet, wherein the spherical magnet has a diameter less than 3 mm and is rotatable about one or more axes to generate a dynamic magnetic field.

12. The system of any of the preceding claims, wherein the system console provides animated visualization of the device relative to anatomy imaged by the probe.

13. The system of any of the preceding claims, further configured for fusion of preoperative MRI images with real-time TRUS images to guide device placement.

14. The system of any of the preceding claims, wherein the plurality of coils comprises 3-12 coils.

15. The system of any of the preceding claims, wherein the tracking antenna array comprise a plurality of coils that are rectangular, free-standing, or wound on a permeable core.

16. The system of any of the preceding claims wherein the one or more sensors comprise one or more shaft-tip coils spaced within 2-5 cm, or up to 5 cm from a needle tip coil.

17. The system of any of the preceding claims, wherein the probe comprises dual or multiple antenna array cubes positioned proximal and distal to the ultrasound crystal arrays.

18. The system of any of the preceding claims, wherein the antenna array cubes are configured to provide a baseline to enhance spatial tracking accuracy.

19. The system of any of the preceding claims, wherein the probe comprises one or more axial crystal arrays.

20. The system of any of the preceding claims, wherein the probe comprises one or more sagittal crystal arrays.- 36 - SG Docket No.: 14676-705.60021. The system of any of the preceding claims, wherein the probe comprises an axial array and a sagittal array, wherein a portion of the axial array overlaps with a portion of the sagittal array.

22. The system of any of the preceding claims, wherein the sensors comprise one or more magnetic, fluxgate, saturable-core, or magnetoresistive sensors, or a combination thereof.

23. The system of any of the preceding claims, wherein the system console is configured to display one or more device animations in real-time relative to multiple imaging planes.

24. The system of any of the preceding claims, wherein the system can be used in combination with transrectal ultrasound (TRUS), endoscopic ultrasound (EUS), intracardiac echocardiography (ICE), transvaginal ultrasound, and / or external ultrasound.

25. The system of any of the preceding claims, wherein the system is configured to deliver therapeutic agents selected from a group consisting of vapor, a pharmacological agent, and a structural agent.

26. The system of any of the preceding claims, further comprising signal processing configured to determine the location and / or orientation using least-squares fitting of sensor voltages and / or gradient tensor calculations.

27. A method for guiding a device within a patient, comprising:inserting a probe comprising an antenna array into the patient;providing a device comprising one or more sensors disposed thereon; generating a magnetic field with the antenna array of the probe; detecting a signal induced in the one or more sensors;determining a location and / or orientation of the one or more sensors; and guiding the device to a target tissue based on the location and / or orientation.

28. A method for guiding a device within a patient, comprising:inserting a probe comprising an antenna array into the patient;providing a device comprising one or more magnetic field generators disposed thereon;generating a magnetic field at the location of the magnetic field generators on the device;measuring magnetic fields induced into each element of the antennae array ; determining a location and / or orientation of the one or more magnetic field generators; and- 37 - SG Docket No.: 14676-705.600guiding the device to a target tissue based on the location and / or orientation.

29. The method of any of the preceding actions, further comprising delivering a therapeutic agent comprising vapor, a pharmacological agent, and / or a structural agent to a target tissue.

30. The method of any of the preceding claims, wherein the probe is a transurethral ultrasound (TRUS) probe.

31. The method of any of the preceding claims, wherein determining the location and / or orientation of the tip-mounted transducer is within a localized tracking volume.

32. The method of any of the preceding claims, wherein the localized tracking volume is less than 200 cubic centimeters.

33. The method of any of the preceding claims, wherein guiding the device further comprises maintaining motion-invariant tracking.

34. The method of any of the preceding claims, comprising capturing an image.

35. The method of any of the preceding claims, further comprising combining a magnetic resonance imaging (MRI) image with the image captured by the probe.

36. The method of any of the preceding claims, wherein the device is a needle.

37. The method of any of the preceding claims, wherein guiding comprises deploying the needle to one or more locations in or near the target tissue.

38. The method of any of the preceding claims, wherein the probe and device move together with the patient to eliminate the need for re-registration.

39. The method of any of the preceding claims, further comprising deploying the needle with one or more overlapping ablation points to cover a target zone.

40. The method of any of the preceding claims, further comprising stepwise rotation of a shaft of the needle with virtual needle deployment to determine optimal placement.

41. The method of any of the preceding claims, further comprising animating a realtime display of the shaft and needle tip on a console.

42. The method of any of the preceding claims, further comprising tracking needle deformation in tissue.

43. The method of any of the preceding claims, further comprising using a plurality of sensors in the probe to increase tracking accuracy.

44. The method of any of the preceding claims, further comprising capturing real-time visualization of delivered vapor.- 38 - SG Docket No.: 14676-705.6005. The method of any of the preceding claims, wherein the needle is configured fordelivery of vapor, a drug, and / or an adhesive.- 39 - SG Docket No.: 14676-705.600

Images