WO2023218425A1

WO2023218425A1 - Systems, apparatuses and methods for activation state control in focused ultrasound based procedures

Info

Publication number: WO2023218425A1
Application number: PCT/IB2023/054944
Authority: WO
Inventors: Avinash Eranki; Megha R
Original assignee: Foundation For Cfhe
Priority date: 2022-05-13
Filing date: 2023-05-12
Publication date: 2023-11-16

Abstract

The invention provides systems, apparatuses and methods for focused ultrasound based tissue intervention. The invention is implemented through a transducer apparatus comprising a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly. The probe assembly comprises a primary ultrasound transducer comprising one or more ultrasound transducer elements, and a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state. The transducer state controller may be configured to selectively change an activation state of at least one ultrasound transducer element within the primary ultrasound transducer based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

Description

Systems. Apparatuses and Methods for Activation State Control in Focused Ultrasound Based Procedures

Field of the Invention

[001] The present invention relates to the domain of tissue procedures. In particular, the invention provides systems, apparatuses and methods of performing a procedure on a subject using focused ultrasound energy, and even more particularly for activation state control in focused ultrasound based procedures.

Background

[002] Solid tumors are one of the most common causes of death in the world, with over a million deaths each year. Solid tumors are treated either with chemotherapy, surgery, or radiation. High intensity focused ultrasound is a new, non-invasive technology that is capable of treating solid tumors by thermal ablation without ionizing radiation. In addition, a new non-invasive, nonionizing, disruptive technology called boiling histotripsy (BH) can perform spatially precise mechanical fractionation of tumor tissue in vivo under real-time ultrasound image guidance, with little or no thermal effects often observed in other thermal ablative technologies.

[003] The use of focused ultrasound energy transducers and devices have however been found to involve certain drawbacks — particularly, for devices that are configured to operate at a derated acoustic intensity (ISPTA) of 720 mW/cm² or above (wherein ISPTA is intensity spatial peak temporal average), and either MI>1.9 (wherein MI is mechanical index) or derated ISPPA > 190 W/cm² (wherein ISPPA is intensity spatial peak pulse average).

[004] Typically, such transducers are not configured for image capabilities that permit for image based guidance or positioning of the trans ducer(s).

[005] Further, such devices are required to be placed in contact with a region-of-interest of a subject’s anatomy or tissue that is under treatment — preferably with a layer of ultrasound gel between the subject’s anatomy and the ultrasound transducer within the device. The ultrasound gel improves conduction of ultrasound energy between the subject’s anatomy and the ultrasound transducer to reduce acoustic impedance and reflection, and to allow for effective focused ultrasound procedures.

[006] It has however been found that owing to irregular shapes of human and animal anatomy, ultrasound transducers are often in contact with surfaces of the anatomy that are non planar (e.g. breast tissue). As a result, despite best efforts of a healthcare provider, there is often insufficient contact between the ultrasound transducer and the region-of-interest of the subject’s anatomy. This is even more the case, where an ultrasound apparatus is being controlled or manipulated by robotic arms or robotic manipulators or an articulating arm.

[007] Air gaps caused by insufficient contact between the ultrasound transducer’s surface and a region-of-interest of the subject’s anatomy can lead to poor or incomplete procedure. Even more problematically, such air gaps can lead to overheating of tissue and consequent burns or tissue trauma. It could also cause permanent damage to the ultrasound transducer by reflecting ultrasoundwaves. This has been found to be particularly difficult in devices having above a derated acoustic intensity (ISPTA) of 720 mW/cm² (wherein ISPTA is intensity spatial peak temporal average), and either MI>1.9 (wherein MI is mechanical index) or derated ISPPA > 190 W/cm² (wherein ISPPA is intensity spatial peak pulse average). The difficulty arises primarily because the energy delivered during ultrasound therapy by such devices is sufficiently high to result in burns or tissue trauma or permanent damage to the ultrasound transducer in case of air gaps or non-sealing contact between the ultrasound transducer and the surface of the subject’s anatomy.

[008] There is accordingly a need for solutions that determine whether an ultrasound transducer has been placed flush against or has complete contact with a region of interest on a subject’s anatomy, and to prevent delivery of ultrasound therapy through improperly positioned ultrasound transducers.

Summary

[009] The invention provides systems, apparatuses and methods for contact based activation state control in focused ultrasound based procedures, for ensuring that ultrasound therapy is only delivered when an ultrasound transducer is in proper contact or in sealing contact with a region- of-interest of a subject’s anatomy, and for eliminating air gaps between an activated ultrasound transducer and a region-of-interest of a patient’s anatomy.

[0010] In an embodiment, the present invention provides a transducer apparatus for focused ultrasound based tissue intervention. The transducer apparatus comprises a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly. The probe assembly comprises a primary ultrasound transducer comprising one or more ultrasound transducer elements. The probe assembly also comprises a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state. The transducer state controller within the transducer apparatus may be configured to selectively change an activation state of at least one ultrasound transducer element within the primary ultrasound transducer based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

[0011] In another embodiment, the present invention provides a method for focused ultrasound based tissue intervention implemented through a transducer apparatus. The transducer apparatus comprises a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly. The probe assembly includes a primary ultrasound transducer comprising one or more ultrasound transducer elements and a set of contact sensors. Each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state. The method comprises the steps of (i) receiving signal(s) from the set of contact sensors, (ii) determining contact states for each contact sensor within the set of contact sensors, wherein determination of the contact states is based on signal(s) received from said contact sensors, (iii) comparing the determined contact states against a predefined contact state threshold requirement, and (iv) selectively changing an activation state of at least one ultrasound transducer element within the primary ultrasound transducer, based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

[0012] The invention also provides a computer program product for focused ultrasound based tissue intervention implemented through a transducer apparatus. The transducer apparatus comprises a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly. The probe assembly includes a primary ultrasound transducer comprising one or more ultrasound transducer elements and a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state. The computer program product comprises a non-transitory computer usable medium having computer readable program code embodied therein, the computer readable program code comprising instructions for implementing at a processor, the steps of (i) receiving signal(s) from the set of contact sensors, (ii) determining contact states for each contact sensor within the set of contact sensors, wherein determination of the contact states is based on signal(s) received from said contact sensors, (iii) comparing the determined contact states against a predefined contact state threshold requirement, and (iv) selectively changing an activation state of at least one ultrasound transducer element within the primary ultrasound transducer, based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

Brief Description of the Accompanying Drawings

[0013] Figure 1 illustrates a system configured for optimizing ultrasound based implementation of tissue diagnosis, tissue therapy, tissue perturbation, tissue fractionation or boiling histotripsy of tissue in accordance with the teachings of the present invention.

[0014] Figure 2 illustrates a transducer apparatus configured for focused ultrasound therapy.

[0015] Figures 3 to 6 illustrate components of a probe assembly configured in accordance with the teachings of the present invention.

[0016] Figure 7 illustrates a method for optimizing ultrasound based implementation of tissue diagnosis, tissue therapy, tissue perturbation, tissue fractionation or boiling histotripsy of tissue in accordance with the teachings of the present invention.

[0017] Figures 8 to 10 illustrate embodiments of components of a probe assembly configured in accordance with the teachings of the present invention.

[0018] Figures 11 to 14 illustrates methods for contact based activation state control in focused ultrasound based therapy, diagnosis or procedures in accordance with the teachings of the present invention.

[0019] Figure 15 illustrates a transducer apparatus configured for contact based activation state control in accordance with the teachings of the present invention.

[0020] Figure 16 illustrates an exemplary system for implementing the present invention. Detailed Description

[0021] The invention provides systems, apparatuses and methods for contact based activation state control in focused ultrasound based procedures, for ensuring that ultrasound therapy is only delivered when an ultrasound transducer is in proper contact or in sealing contact with a region- of-interest of a subject’s anatomy. The invention reduces or eliminates air gaps between an activated ultrasound transducer and a region-of-interest of a patient’s anatomy.

[0022] The invention provides a transducer apparatus that is configured for safely and accurately directing focused ultrasound energy towards a tissue mass — for example, for perturbing, ablating, or fractionating the tissue mass or for implementing boiling histotripsy.

[0023] The invention enables implementation of contact based activation state control, for ensuring that ultrasound therapy is only delivered when an ultrasound transducer is in proper contact or in sealing contact with a region-of-interest of a subject’s anatomy.

[0024] The above systems, apparatuses and methods are described in more detail below.

[0025] Figure 1 illustrates a system 100 for delivery of focused ultrasound energy towards a tissue mass — for example, for perturbing or fractionating the tissue mass or for implementing boiling histotripsy.

[0026] System 100 comprises a transducer apparatus 102. The transducer apparatus comprises an ultrasound transducer capable of directing focused ultrasound energy towards a tissue mass. The focused ultrasound energy may be delivered to tissue for any purpose including perturbing or ablating or fractionating the tissue mass or implementing boiling histotripsy. In an embodiment the ultrasound transducer is a focused ultrasound transducer. Transducer apparatus 102 may optionally include at least one additional ultrasound transducer. In one embodiment, the at least one additional ultrasound transducer is a second ultrasound transducer. In another embodiment, the at least one additional ultrasound transducer is a passive cavitation detector.

[0027] The ultrasound transducer is driven by a radio frequency (RF) amplifier 106, which is in turn controlled by a waveform generator 104. A waveform may be set or defined or input through one or more control parameters at waveform generator 104 — and this waveform is then amplified and used to drive the ultrasound transducer within transducer apparatus 102. The generated waveform may be viewed on digital oscilloscope 108. The waveform set or selected for generation by waveform generator will be selected based on the bioeffect desired to be produced in vivo at or on the region-of-interest or tissue-of-interest. Each of digital oscilloscope 108, waveform generator 104 and transducer apparatus may be controlled by a computer 110 configured for data acquisition and control, and may each be configured to transmit data signals back to computer 110 to enable a viewer or operator to view feedback from each such device.

[0028] Figure 2 illustrates an embodiment 200 of the transducer apparatus 102 that has been more generally described in connection with Figure 1.

[0029] Transducer apparatus 200 comprises a probe assembly 202. Probe assembly 202 comprises a primary ultrasound transducer capable of delivering ultrasound waves for perturbing or ablating or fractionating the tissue mass or for implementing boiling histotripsy. In an embodiment the primary ultrasound transducer is a focused ultrasound transducer. Probe assembly 202 may additionally include at least one additional ultrasound transducer. In one embodiment, the at least one additional ultrasound transducer is a second ultrasound transducer. In another embodiment, the at least one additional ultrasound transducer is a passive cavitation detector. In a particular embodiment, the additional ultrasound transducer is positioned coaxially relative to the primary ultrasound transducer, within probe assembly 202. In one embodiment, probe assembly 202 may include both of a second ultrasound transducer and a passive cavitation detector positioned coaxially relative to the primary ultrasound transducer. In an embodiment, probe assembly 202 may only include a primary ultrasound transducer without either of a second ultrasound transducer and a passive cavitation detector.

[0030] Transducer apparatus 200 additionally includes a probe assembly holder 204 — comprising a holder for, or an assembly for holding probe assembly 202. In an embodiment (illustrated in Figure 3), probe assembly holder 204 may comprise a casing or housing within which the primary ultrasound transducer and optionally the at least one additional ultrasound transducer are either partially or wholly housed coaxially relative to each other. In a particular embodiment the probe assembly holder 204 comprises a housing configured to house a primary ultrasound transducer 2022 (e.g. a first focused ultrasound transducer) and the additional ultrasound transducer 2024, such that the additional ultrasound transducer 2024 is disposed partially or wholly within a cavity or hole 2026 formed along the central axis of the primary ultrasound transducer 2022.

[0031] Probe assembly holder 204 is affixed to or coupled with probe manipulation assembly 206. Probe manipulation assembly 206 comprises an assembly configured to enable probe assembly 202 to be moved, positioned or manipulated along or about the x, y and / or z axes. In certain embodiments, probe manipulation assembly 206 comprises an assembly configured to confer on probe assembly 202, any of 3, 4, 5 or 6 degrees of freedom. In an embodiment, probe manipulation assembly 206 comprises any of (i) a linear stage exhibiting translation about a single axis, (ii) a motion stage configured for translation about two perpendicular axes, (iii) a motion stage configured for translation about three perpendicular axes, (iv) an articulated arm assembly comprising a plurality of interconnected arms, wherein one or more arms is / are pivotably interconnected to at least other arm in a manner that enables manipulation of probe assembly 202 along or about the x, y and / or z axes, or to confer on probe assembly 202, any of 3, 4, 5 or 6 degrees of freedom, (v) an articulated arm assembly comprising a first arm and a second arm that are pivotably interconnected, wherein the articulated arm assembly is configured to enable manipulation of probe assembly 202 along or about the x, y and / or z axes, or to confer on probe assembly 202, any of 3, 4, 5 or 6 degrees of freedom, and (vi) a robotic arm assembly configured to enable robotic manipulation of probe assembly 202 along or about the x, y and / or z axes, or to confer on probe assembly 202, any of 3, 4, 5 or 6 degrees of freedom. Probe manipulation assembly 206 may be controlled either manually or through a computer application program implemented through a computer 110. The probe manipulation assembly may be controlled either through wired or wireless controllers — enabling a physician or operator to perform gross positioning of probe assembly 202 (or the transducer(s) therewithin) optimally relative to a subject’s anatomy or relative to a region-of-interest / tissue-of-interest within a subject’s anatomy. [0032] Transducer apparatus 200 may additionally include signal transmission infrastructure 208 comprising a bus or interconnections between one or more components of transducer apparatus 200 and / or between transducer apparatus 200 and one or more components of system 100 — to enable signalling or transmitting and receiving of signals therebetween.

[0033] Figure 3 illustrates an exemplary configuration for probe assembly 202 within transducer apparatus 200. As illustrated in Figure 3, probe assembly 202 comprises a primary ultrasound transducer 2022 having a cavity or hole 2026 extending therethrough along a central axis. At least one additional ultrasound transducer 2024 is positioned coaxially to primary ultrasound transducer 2022 about the central axis, such that primary ultrasound transducer 2022 can deliver ultrasound wavelengths onto a target region on a subject, for example for tissue perturbation / tissue fractionation purposes or ablation or boiling histotripsy, while the additional ultrasound transducer can simultaneously transmit and/ or receive image data signals (such as ultrasound wavelengths) through the cavity or hole 2026 that extends through primary ultrasound transducer 2022 — for implementing its imaging functionality without interfering with the therapy / perturbation / fractionation related functionality of primary ultrasound transducer 2022. In some embodiments imaging data from additional ultrasound transducer 2024 may be used for real time imaging purposes — to enable safe and accurate manipulation and positioning of probe assembly 202 and I or transducer apparatus 200 relative to a region-of-interest or a target region on or within a subject’s anatomy. In an embodiment, imaging signals generated by the additional ultrasound transducer 2024 generate images that are displayed on a display device for communicating position or orientation information corresponding to probe assembly 202. It would be understood that while the embodiment of the probe assembly 202 that is illustrated in Figure 3 is shown with both of a primary ultrasound transducer 2022 and an additional ultrasound transducer 2024, in other embodiments, the probe assembly 202 may only comprise a primary ultrasound transducer 2022 without any additional ultrasound transducer 2024.

[0034] Figure 4 illustrates a plan view of a probe assembly 202 having a primary ultrasound transducer 2022. In an embodiment, an additional ultrasound transducer 2024 is arranged coaxially relative to the primary ultrasound transducer 2022 —wherein additional ultrasound transducer 2024 is positioned within or is aligned with a cavity 2026 extending through primary ultrasound transducer 2022. The plan view of Figure 4 may be understood as a view of probe assembly 202 showing a surface of primary ultrasound transducer 2022 that would be positioned proximal to a region-of-interest or tissue-of-interest during operation of primary ultrasound transducer 2022.

[0035] Figure 5 illustrates a second plan view of a probe assembly 202 wherein primary ultrasound transducer 2022 and the additional ultrasound transducer 2024 are arranged coaxially relative to each other — and wherein additional ultrasound transducer 2024 is positioned within or is aligned with a cavity 2026 extending through primary ultrasound transducer 2022. The plan view of Figure 5 may be understood as a view of probe assembly 202 showing a surface of primary ultrasound transducer 2022 that would be positioned distal to a region-of-interest or tissue-of-interest during operation of primary ultrasound transducer 2022. As shown, the primary ultrasound transducer 2022 may be provided with one or more fasteners, or affixing elements, or tapped holes 2028 for affixing primary ultrasound transducer 2022 to probe assembly holder 204. In an embodiment, the primary ultrasound transducer 2022 may be affixed to probe assembly holder 204 by engaging fasteners, affixing elements, or tapped holes 2028 with an adapter plate, which is in turn coupled with probe assembly holder 204.

[0036] Figure 6 illustrates various components of transducer apparatus 200. As shown in Figure 6, transducer apparatus may comprise probe assembly 202 — wherein probe assembly 202 comprises a primary ultrasound transducer 2022 and an additional ultrasound transducer 2024 arranged coaxially relative to each other. A contact surface 2030 may be provided on a surface of primary ultrasound transducer 2022 that is proximal to a region-of-interest or tissue-of-interest during operation of primary ultrasound transducer 2022 — for example a gel pad or other pad for contacting a surface 600 of a subject’s anatomy. Transducer apparatus 200 is additionally shown as having signal transmission infrastructure 208 comprising interconnections between one or more components of transducer apparatus 200 and / or between transducer apparatus 200 and one or more components of system 100 — to enable signalling or transmitting and receiving of signals therebetween.

[0037] In an embodiment of the invention, transducer apparatus 200 may be configured such that probe manipulation assembly 206 is only operatable when the primary ultrasound transducer 2022 (e.g. a focused ultrasound transducer) is in a deactivated state.

[0038] In another embodiment of the invention, transducer apparatus 200 may be configured such that the primary ultrasound transducer 2022 (e.g. a focused ultrasound transducer) is deactivated in response to detection of movement, repositioning or reorientation of probe manipulation assembly 206 or probe assembly 202, or in response to detection of a signal for implementing movement, repositioning or reorientation of probe manipulation assembly 206 or probe assembly 202.

[0039] In another embodiment of the invention, the transducer apparatus 200 may be configured such that (i) the primary ultrasound transducer 2022 (e.g. a focused ultrasound transducer) and the additional ultrasound transducer 2024 are activatable when the probe assembly is static, and (ii) only the additional ultrasound transducer 2024 is activatable when the probe assembly 202 or the probe manipulation assembly 206 is moving.

[0040] In an embodiment of the transducer apparatus 200, primary ultrasound transducer 2022 of the probe assembly is an ultrasound transducer capable of performing fractionation or ablation or perturbation or boiling histotripsy of tissue cells or tumour cells in the range of a few hundred microns, at multiple spatial locations with each tumour/ cyst/ nodule/ etc. The frequency at which the primary ultrasound transducer 2022 operates may be between 200 kHz and 10 MHz. In a particular embodiment, the primary ultrasound transducer 2022 of the probe assembly is configured to operate at a derated acoustic intensity (ISPTA) of 720 mW/cm² or above (wherein ISPTA is intensity spatial peak temporal average), and either MI>1.9 (wherein MI is mechanical index) or derated ISPPA > 190 W/cm² (wherein ISPPA is intensity spatial peak pulse average).

[0041] In an embodiment of the invention, primary ultrasound transducer 2022 of the probe assembly is a focused ultrasound transducer configured for operation with, or controlled to operate within the below operating parameter ranges:

[0042] In an embodiment of the invention, where probe assembly 202 includes at least one additional ultrasound transducer 2024 — and wherein the at least one additional ultrasound transducer 2024 is a second ultrasound transducer, the second ultrasound transducer is configured to operate under a set of operating parameters that is different from the set of operating parameters under which the primary ultrasound transducer 2022 is configured to operate. In a specific embodiment, the second ultrasound transducer is configured to implement B-mode or pulsed Doppler or color Doppler or elastography imaging for positioning and localization of probe assembly 202 relative to a region-of-interest or tissue-of-interest, within the below set of operating parameters:

[0043] In an embodiment of the invention, where probe assembly 202 includes at least one additional ultrasound transducer 2024 — and wherein the at least one additional ultrasound transducer 2024 is a passive cavitation detector, the passive cavitation detector is configured to operate under a set of operating parameters that is different from the set of operating parameters under which the primary ultrasound transducer 2022 is configured to operate. In a specific embodiment, the passive cavitation detector can be spherical or cylindrical in shape and is configured to operate within the below set of operating parameters:

[0044] Figure 7 illustrates a method for optimizing ultrasound based implementation of implementation of any of tissue diagnosis, tissue therapy, tissue perturbation, tissue fractionation or boiling histotripsy or any other tissue procedures or therapy procedures in accordance with the teachings of the present invention. In an embodiment, the method of Figure 7 may be implemented by operation of any of the embodiments of transducer apparatus 200 that has been described above.

[0045] Step 702 comprises activating a first transducer within probe assembly 202 for obtaining data representing a position of an ultrasound probe assembly relative to an anatomical object (for example a region-of-interest, tissue-of-interest, anatomical surface, tumour, cyst, nodule, etc.), wherein the first transducer operates under a first set of operating parameters. The first transducer activated at step 702 may comprise the imaging transducer 2024 of probe assembly 202 that has been described hereinabove, - wherein during an activated state said first transducer can simultaneously transmit or receive signals (such as audio wave signals or ultrasound wavelengths) through a cavity or hole 2026 that extends through a coaxially positioned primary ultrasound transducer 2022 — for implementing its imaging functionality without interfering with the therapy I perturbation / fractionation related functionality of the coaxially disposed primary ultrasound transducer 2022.

[0046] In an embodiment, where the first transducer is an ultrasound transducer, the ultrasound transducer is configured to operate under a first set of operating parameters In a specific embodiment, the first transducer is an ultrasound transducer that is configured to implement B- mode imaging for positioning and localization of probe assembly 202 relative to a region-of- interest or tissue-of-interest, within the below set of operating parameters:

[0047] In another embodiment where the first transducer is a passive cavitation detector, the passive cavitation detector is configured to operate under a first set of operating parameters. In a specific embodiment, the passive cavitation detector can be spherical or cylindrical in shape and is configured to operate within the below set of operating parameters:

[0048] Step 704 comprises generating and displaying on a display, one or more image (s) based on signals received from the first transducer. The images may be displayed on a display associated with a computer being operated by an operator or physician and provides positional / locational information concerning the position and / or orientation of the probe assembly 202 relative to a subject’s anatomy.

[0049] Step 706 comprises manipulating the probe assembly 202 to an intended position and / or orientation relative to the anatomical object — wherein said manipulation involves changing a position or orientation of the probe assembly 202 relative to the anatomical object by manipulating or manipulation of probe manipulation assembly 206. The manipulation of probe assembly at step 706 may continue until the operator or physician determines, based on images displayed on the display (i.e. images generated by data signals received from the first transducer), that the probe assembly has been moved to an appropriate or intended or desired position or orientation relative to the anatomical object.

[0050] Step 708 comprises activating a second transducer within probe assembly 202 to direct high intensity focused ultrasound waves onto a target region. In an embodiment, the second transducer operates under a second set of operating parameters that are (i) distinct from the first set of operating parameters and (ii) are selected for tissue perturbation, or tissue fractionation or boiling histotripsy. In an embodiment, the second transducer is a primary ultrasound transducer — and is configured such that during an activated state, the second transducer directs high intensity focused ultrasound wavelengths on a target region (such as the anatomical object) according to the below second set of operating parameters.

[0051] In a particular embodiment, the second transducer is a primary ultrasound transducer — and is configured to operate at a derated acoustic intensity (ISPTA) of 720 mW/cm² or above (wherein ISPTA is intensity spatial peak temporal average), and either MI> 1.9 (wherein MI is mechanical index) or derated ISPPA > 190 W/cm² (wherein ISPPA is intensity spatial peak pulse average) .

[0052] Figures 8 to 10 illustrate embodiments of components of a probe assembly 202 configured in accordance with the teachings of the present invention.

[0053] Figure 8 illustrates a plan view of a probe assembly 202 having a primary ultrasound transducer 2022. Primary ultrasound transducer 2022 has a defined first active surface region 2023 configured for emission of ultrasoundwaves. The external perimeter of active surface region 2023 is surrounded by an inactive surface region 2025 which does not emit ultrasound waves. Inactive surface region 2025 may comprise either part of primary ultrasound transducer 2022, or may comprise part of a housing within which primary ultrasound transducer 2022 is held, or to which housing primary ultrasound transducer 2022 has been affixed. One or more contact sensors 2027 are disposed or located within the inactive surface region 2025 — wherein each contact sensor 2027 is configured to generate an electrical signal identifying a contact state (i.e. contact or a lack of contact with another surface).

[0054] Contact sensors 2027 may comprise any type of sensor capable of being used to identify contact or a lack of contact with another surface, and byway of non-limiting examples each contact sensor 2027 may comprise any of a pressure sensor, a strain gauge, a capacitive sensor, a piezo electric sensor, pressure sensor, an ultrasonic sensor, an acoustic sensor, a resistance sensor (in particular for measuring the body resistance), an electromyography sensor, a near infrared spectroscopy (NIRS) sensor, or any other sensor that is capable of determining whether said sensor is in contact with an adjacent surface, or even more particularly whether said sensor is in contact with an anatomical surface of a subject.

[0055] Probe assembly 202 may be configured such that signals from each contact sensor 2027 are transmitted to a computing device or a controller configured to determine whether said contact sensor 2027 is in contact with an adjacent surface, or whether said sensor is in contact with an anatomical surface of a subject. Locating the contact sens or (s) within the inactive surface region 2025 of the probe assembly 202, ensures that the contact sensors 2027 do not interfere with operation and emission of ultrasound waves from the active surface region 2023 of the probe assembly 202, and that ultrasound waves emitted from the active surface region 2023 can be directed without interference onto a region-of-interest or tissue-of-interest within a subject’s anatomy. In certain embodiments however, one or more contact sensors may be located within the active surface region 2023 of the probe assembly 202.

[0056] While the embodiment of Figure 8 illustrates contact sensors 2027 being distributed in a substantially equally spaced configuration around an external circular periphery of the active surface region 2023, it would be understood that the number of contact sensors 2027 and their relative spacing and pattern of distribution can vary according to several factors including the shape of the probe assembly 202, shape of the housing within which the primary ultrasound transducer 2022 is held, shape and / or size of the active surface region 2023, shape and / or size of the inactive surface region 2025, and / or size, shape and operating capabilities of the contact sensors 2027 themselves.

[0057] Figure 9 illustrates a plan view of another embodiment of probe assembly 202 having a primary ultrasound transducer 2022 and an additional ultrasound transducer 2024 that is arranged coaxially relative to the primary ultrasound transducer 2022. The additional ultrasound transducer 2024 is positioned within or is aligned with a cavity 2026 extending through primary ultrasound transducer 2022. The plan view of Figure 9 may be understood as a view of probe assembly 202 showing a surface of primary ultrasound transducer 2022 that would be positioned proximal to a region-of-interest or tissue-of-interest during operation of primary ultrasound transducer 2022.

[0058] Primary ultrasound transducer 2022 has a defined active surface region 2023 from which ultrasound waves are emitted. The external perimeter of active surface region 2023 is surrounded by a first inactive surface region 2025 which does not emit ultrasound waves. The first inactive surface region 2025 may comprise either part of primary ultrasound transducer 2022, or may comprise part of a housing within which primary ultrasound transducer 2022 is held, or to which housing primary ultrasound transducer 2022 has been affixed. One or more contact sensors 2027 are disposed or located within the first inactive surface region 2025 — wherein each contact sensor 2027 is configured to generate an electrical signal identifying contact or a lack of contact with another surface.

[0059] Additionally, a second inactive surface region 2029 surrounds cavity 26 — such that the second inactive surface region is formed between an external peripheral boundary of the additional ultrasound transducer 2024 and an internal peripheral boundary of the active surface region 2023 of the primary ultrasound transducer 2022. The second inactive surface region 2029 does not emit ultrasound waves. The second inactive surface region 2029 may comprise either part of primary ultrasound transducer 2022, or may comprise part of the housing within which primary ultrasound transducer 2022 is held, or to which housing primary ultrasound transducer 2022 has been affixed, or may simply comprise a gap or space between an external periphery of the additional ultrasound transducer 2024 and an internal periphery of the active surface region 2023 of the primary ultrasound transducer 2022. One or more contact sensors 2031 are disposed or located within the second inactive surface region 2029 — wherein each contact sensor 2027 is configured to generate an electrical signal identifying contact or a lack of contact with another surface.

[0060] Contact sensors 2027, 2031 as described in the embodiment of Figure 9 may comprise any type of sensor capable of being used to identify contact or a lack of contact with another surface, and by way of non-limiting examples each contact sensor 2027, 2031 may comprise any of a pressure sensor, a strain gauge, a capacitive sensor, a piezo electric sensor, pressure sensor, an ultrasonic sensor, an acoustic sensor, a resistance sensor (in particular for measuring the body resistance), an electromyography sensor, a near infrared spectroscopy (NIRS) sensor, or any other sensor that is capable of determining whether said sensor is in contact with an adjacent surface, or even more particularly whether said sensor is in contact with an anatomical surface of a subject.

[0061] Probe assembly 202 may be configured such that signals from each contact sensor 2027, 2031 are transmitted to a computing device or a controller configured to determine whether said contact sensor 2027, 2031 is in contact with an adjacent surface, or whether said sensor is in contact with an anatomical surface of a subject. Locating the contact sensor(s) within the inactive surface regions 2025, 2029 of the probe assembly 202, ensures that the contact sensors 2027, 2031 do not interfere with operation and emission of ultrasound waves from the active surface region 2023 of the probe assembly, and that ultrasound waves emitted from the active surface region 2023 can be directed without interference onto a region-of-interest or tissue-of-interest within a subject’s anatomy.

[0062] While the embodiment of Figure 9 illustrates contact sensors 2027, 2031 being distributed in a substantially equally spaced configuration around external and internal circular peripheries of the active surface region 2023, it would be understood that the number of contact sensors 2027, 2031 and their relative spacing and pattern of distribution can vary according to several factors including the shape of the probe assembly 202, shape of the housing within which the primary ultrasound transducer 2022 is held, shape and / or size of the active surface region 2023, shape and I or size of the inactive surface region 2025, 2029, shape and size of the additional ultrasound transducer 2024, and / or size, shape and operating capabilities of the contact sensors 2027, 2031 themselves.

[0063] It would be understood that by providing for contact sensors 2027, 2031 around external and internal circular peripheries of the active surface region 2023, the embodiment of Figure 9 provides for improved detection of contact between the active surface region 2023 and a subject’s anatomy, since any air gaps or insufficient contact in the region of either the external or internal periphery of the active surface region 2023 can be detected by contact sensors 2027, 2031.

[0064] Figure 10 illustrates a plan view of a more particular embodiment of the probe assembly 202 as illustrated in Figure 9. In the more particular embodiment shown in Figure 10, active surface region 2023 from which ultrasound waves are emitted is formed from a plurality or array of ultrasound transducer elements 2033. In an embodiment of the invention, each ultrasound transducer element 2033 is independently activatable or deactivatable (i.e. can be activated to emit ultrasound waves or deactivated to cease emitting ultrasound waves independent of an activation or deactivation state of other ultrasound transducer elements within active surface region 2023.

[0065] While in the embodiment of Figure 10, the active surface region 2023 is shown as being formed from a plurality of adjacently positioned arcuate sector shaped ultrasound transducer elements, it would be understood that the ultrasound transducer elements 2033 may have any shape or configuration that allow them to be adjacently positioned or assembled to form a larger active surface region 2023. For example, the ultrasound transducer elements 2033 may comprise any of square, rectangular, triangular, trapezoidal, parallelepiped, pentagonal, hexagonal, octagonal or concentric annular shaped transducer element. In assembling or forming active surface region

2023, a plurality of ultrasound transducer elements 2033 are placed adjacent to one another such that adjacently positioned ultrasound transducer elements 2033 have inactive boundary surface regions 2035 formed between two adjacently positioned transducer elements 2033 — wherein said inactive boundary surface regions 2035 do not emit ultrasound waves. One or more contact sensors 2037 are disposed or located within said inactive boundary surface regions 2035 — wherein each contact sensor 2037 is configured to generate an electrical signal identifying contact or a lack of contact with another surface.

[0066] Contact sensors 2027, 2031, 2037 as described in the embodiment of Figure 10 may comprise any type of sensor capable of being used to identify contact or a lack of contact with another surface, and by way of non-limiting examples each contact sensor 2027, 2031, 2037 may comprise any of a pressure sensor, a strain gauge, a capacitive sensor, a piezo electric sensor, pressure sensor, an ultrasonic sensor, an acoustic sensor, a resistance sensor (in particular for measuring the body resistance), an electromyography sensor, a near infrared spectroscopy (NIRS) sensor, or any other sensor that is capable of determining whether said sensor is in contact with an adjacent surface, or even more particularly whether said sensor is in contact with an anatomical surface of a subject.

[0067] Probe assembly 202 may be configured such that signals from each contact sensor 2027, 2031, 2037 are transmitted to a computing device or a controller configured to determine whether said contact sensor 2027, 2031, 2037 is in contact with an adjacent surface, or whether said sensor is in contact with an anatomical surface of a subject. Locating the contact sensor(s) within the inactive surface regions 2025, 2029 of the probe assembly 202, and within inactive boundary surface regions 2035 formed between adjacently positioned between adjacent boundaries of ultrasound transducer elements 2033 of probe assembly 202, ensures that the contact sensors 2027, 2031, 2037 do not interfere with operation and emission of ultrasound waves from the active surface region 2023 of the probe assembly, and that ultrasound waves emitted from the active surface region 2023 can be directed without interference onto a region-of-interest or tissue-of- interest within a subject’s anatomy.

[0068] While the embodiment of Figure 10 illustrates contact sensors 2027, 2031, 2037 being distributed in a substantially equally spaced configuration around external and internal circular peripheries of the active surface region 2023, and across the inactive boundary surface regions 2035, it would be understood that the number of contact sensors 2027, 2031, 2037 and their relative spacing and pattern of distribution can vary according to several factors including the shape of the probe assembly 202, shape of the housing within which the primary ultrasound transducer 2022 is held, shape and / or size of the active surface region 2023, shape and / or size of the inactive surface region 2025, 2029, shape and size of the additional ultrasound transducer

2024, shape and / or size of the ultrasound transducer elements 2033 that are assembled to form an active surface region 2023, shape and / or size of the inactive boundary surface regions 2035, and I or size, shape and operating capabilities of the contact sensors 2027, 2031, 2037 themselves.

[0069] It would be understood that by providing for contact sensors 2027, 2031, 2037 around external and internal circular peripheries of the active surface region 2023, and at the inactive boundary surface regions 2035 formed between adjacently positioned ultrasound transducer elements 2033, the embodiment of Figure 9 provides for improved detection of contact between the active surface region 2023 and a subject’s anatomy, since any air gaps or insufficient contact in the region of either the external or internal periphery of the active surface region 2023, or even at specific localized positions within the active surface region 2023 can be detected by contact sensors 2027, 2031, 2037.

[0070] Figure 11 illustrates a method for contact based activation state control in focused ultrasound based therapy, diagnosis or procedures in accordance with the teachings of the present invention. In an embodiment, the method of Figure 11 may be implemented through a probe assembly 202 configured in accordance with the embodiments described in connection with any one of Figures 8 to 10 hereinabove.

[0071] Step 1102 comprises receiving signal(s) from a set of contact sensors provided within the probe assembly 202. The set of contact sensors may comprise one or more contact sensors 2027, 2031, 2037, disposed within the probe assembly — preferably in locations that are outside of an active surface region 2023 of a primary ultrasound transducer 2022. The signal(s) received from said set of contact sensors may comprise an electrical signal representing a contact state or a contact event detected by one or more contact sensors within the set of contact sensors. The signal(s) may be received at a computing device, processor, interface or controller configured to receive signal(s) from contact sensors disposed within probe assembly 202.

[0072] Step 1104 comprises determining contact states for each contact sensor within the set of contact sensors, based on signal(s) received from said contact sensors. The determination at step 1104 may be implemented at the computing device, processor, interface or controller at which the signal(s) from contact sensors disposed within probe assembly 202 are received. In an embodiment, each contact state determined at step 1104 may comprise one of (i) a state wherein the corresponding contact sensor is in contact with a surface positioned adjacent to said one or more contact sensors (i.e. a positive contact state) and (ii) a state wherein the corresponding contact sensor is not in contact with any surface (i.e. a negative contact state).

[0073] The determined contact states (or the set of determined contact states corresponding to the set of contact sensors) are compared against a predefined contact state threshold requirement (i.e. a predefined set of contact state rules) to determine whether a primary ultrasound transducer 2022 (or specific regions thereof) is sufficiently or properly in contact with a surface of a subject’s anatomy or with a surface of a region-of-interest on the subject’s anatomy. In an embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, at which (or above which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered sufficiently or properly in contact with a surface of a subject’s anatomy or with a surface of a region-of-interest on the subject’s anatomy. In another embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, below which (or at which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered insufficiently or improperly in contact with an surface of a subject’s anatomy or with a surface of a region-of-interest on the subject’s anatomy. [0074] Step 1106 comprises responding to a determination that the contact states satisfy a predefined contact state threshold requirement, by implementing an activated state (i) at the primary ultrasound transducer 2022 within probe assembly 202, or (ii) at one or more independently activatable ultrasound transducer elements 2033, transducer element arrays or sectored transducer element arrays within the probe assembly - wherein in the activated state, the corresponding ultrasound transducer 2022 or the corresponding ultrasound transducer element(s) I array(s) emit(s) and direct(s) focused ultrasound waves onto a region-of-interest or target region (for example, a region on a subject’s anatomy).

[0075] In an embodiment, step 1106 comprises responding to a determination that the contact states satisfy a predefined contact state threshold requirement, by implementing an activated state for the entire primary ultrasound transducer 2022 or for the entire active surface region 2023 of the ultrasound transducer 2022. In another embodiment, step 1106 comprises responding to a determination that the contact states corresponding to a sub-set of contact sensors disposed within the probe assembly satisfy a predefined contact state threshold requirement, by selectively implementing (i) an activated state for one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors within the sub-set of contact sensors that satisfy a predefined contact state threshold requirement — wherein in the activated state said one or more ultrasound transducer elements 2033 emit ultrasound waves, and (ii) a deactivated state for one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors that do not satisfy the predefined contact state threshold requirement — wherein in the deactivated state said deactivated one or more ultrasound transducer elements 2033 do not emit ultrasound waves. By selectively activating and / or deactivating individual ultrasound transducer elements 2033 based on determined contact states corresponding to contact sensors in the vicinity of said individual ultrasound transducer elements 2033, the method enables steerable or selective activation of only specific portions of the primary ultrasound transducer 2022 that are sufficiently or properly in contact with a subject’s anatomy, while deactivating portions of the primary ultrasound transducer 2022 that have insufficient contact with (or air gaps separating) a surface of the subject’s anatomy.

[0076] Figure 12 illustrates a second method for contact based activation state control in focused ultrasound based therapy, diagnosis or procedures in accordance with the teachings of the present invention. In an embodiment, the method of Figure 12 may be implemented through a probe assembly 202 configured in accordance with the embodiments described in connection with any one of Figures 8 to 10 hereinabove.

[0077] Step 1202 comprises receiving signal(s) from a set of contact sensors provided within the probe assembly 202. The set of contact sensors may comprise one or more contact sensors 2027, 2031, 2037, disposed within the probe assembly — preferably in locations that are outside of an active surface region 2023 of a primary ultrasound transducer 2022. The signal(s) received from said set of contact sensors may comprise an electrical signal representing a contact state or a contact event detected by one or more contact sensors within the set of contact sensors. The signal(s) may be received at a computing device, processor, interface or controller configured to receive signal(s) from contact sensors disposed within probe assembly 202. [0078] Step 1204 comprises determining contact states for each contact sensor within the set of contact sensors, based on signal(s) received from said contact sensors. The determination at step 1204 may be implemented at the computing device, processor, interface or controller at which the signal(s) from contact sensors disposed within probe assembly 202 are received. In an embodiment, each contact state determined at step 1204 may comprise one of (i) a state wherein the corresponding contact sensor is in contact with a surface positioned adjacent to said one or more contact sensors (i.e. a positive contact state) and (ii) a state wherein the corresponding contact sensor is not in contact with any surface (i.e. a negative contact state).

[0079] The determined contact states (or the set of determined contact states corresponding to the set of contact sensors) are compared against a predefined contact state threshold requirement (i.e. a predefined set of contact state rules) to determine whether a primary ultrasound transducer 2022 (or specific regions thereof) is sufficiently or properly in contact with a surface of a subject’s anatomy or with a surface of a region-of-interest on the subject’s anatomy. In an embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, at which (or above which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered sufficiently or properly in contact with an surface of a subject’s anatomy orwith a surface of a region-of-interest on the subject’s anatomy. In another embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, below which (or at which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered insufficiently or improperly in contact with a surface of a subject’s anatomy orwith a surface of a region-of-interest on the subject’s anatomy.

[0080] Step 1206 comprises responding to a determination that the contact states do not satisfy a predefined contact state threshold requirement, by implementing a deactivated state (i) at the primary ultrasound transducer 2022 within probe assembly 202, or (ii) at one or more independently activatable ultrasound transducer elements 2033, transducer element arrays or sectored transducer element arrays within the probe assembly - wherein in the deactivated state, the corresponding ultrasound transducer 2022 or the corresponding ultrasound transducer element(s) / array (s) does not emit ultrasound waves.

[0081] In an embodiment, step 1206 comprises responding to a determination that the contact states do not satisfy a predefined contact state threshold requirement, by implementing a deactivated state for the entire primary ultrasound transducer 2022 or for the entire active surface region 2023 of the ultrasound transducer 2022. In another embodiment, step 1206 comprises responding to a determination that the contact states corresponding to a sub-set of contact sensors disposed within the probe assembly do not satisfy a predefined contact state threshold requirement, by selectively implementing (i) a deactivated state for one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors within the sub-set of contact sensors that do not satisfy a predefined contact state threshold requirement — wherein in the deactivated state said one or more ultrasound transducer elements 2033 do not emit ultrasound waves, and (ii) an activated state for one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors that satisfy the predefined contact state threshold requirement — wherein in the activated state said activated one or more ultrasound transducer elements 2033 emit ultrasound waves. By selectively activating and / or deactivating individual ultrasound transducer elements 2033 based on determined contact states corresponding to contact sensors in the vicinity of said individual ultrasound transducer elements 2033, the method enables steerable or selective deactivation of only specific portions of the primary ultrasound transducer 2022 that are insufficiently or improperly in contact with a subject’s anatomy, while activating portions of the primary ultrasound transducer 2022 that have sufficient contact with (and therefore no air gaps separating) a surface of the subject’s anatomy.

[0082] Figure 13 illustrates a third method for contact based activation state control in focused ultrasound based therapy, diagnosis or procedures in accordance with the teachings of the present invention. In an embodiment, the method of Figure 13 may be implemented through a probe assembly 202 configured in accordance with the embodiments described in connection with any one of Figures 8 to 10 hereinabove.

[0083] Step 1302 comprises receiving signal(s) from a set of contact sensors provided within the probe assembly 202. The set of contact sensors may comprise one or more contact sensors 2027, 2031, 2037, disposed within the probe assembly — preferably in locations that are outside of an active surface region 2023 of a primary ultrasound transducer 2022. The signal(s) received from said set of contact sensors may comprise electrical signal(s) representing a contact state or a contact event detected by one or more contact sensors within the set of contact sensors. The signal(s) may be received at a computing device, processor, interface or controller configured to receive signal(s) from contact sensors disposed within probe assembly 202.

[0084] Step 1304 comprises determining contact states for each contact sensor within the set of contact sensors, based on signal(s) received from said contact sensors. The determination at step 1304 may be implemented at the computing device, processor, interface or controller at which the signal(s) from contact sensors disposed within probe assembly 202 are received. In an embodiment, each contact state determined at step 1304 may comprise one of (i) a state wherein the corresponding contact sensor is in contact with a surface positioned adjacent to said one or more contact sensors (i.e. a positive contact state) and (ii) a state wherein the corresponding contact sensor is not in contact with any surface (i.e. a negative contact state).

[0085] The determined contact states (or the set of determined contact states corresponding to the set of contact sensors) are compared against a predefined contact state threshold requirement (i.e. a predefined set of contact state rules) to determine whether a primary ultrasound transducer 2022 (or specific regions thereof) is sufficiently or properly in contact with a surface of a subject’s anatomy or with a surface of a region-of-interest on the subject’s anatomy. In an embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, at which (or above which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered sufficiently or properly in contact with an surface of a subject’s anatomy orwith a surface of a region-of-interest on the subject’s anatomy. In another embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, below which (or at which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered insufficiently or improperly in contact with a surface of a subject’s anatomy orwith a surface of a region-of-interest on the subject’s anatomy. [0086] Step 1306 comprises responding to a determination that the contact states satisfy a predefined contact state threshold, by switching (i) a primary ultrasound transducer 2022 within the probe assembly 202, or (ii) one or more independently activatable ultrasound transducer elements 2033, transducer element arrays or sectored transducer element arrays within the probe assembly 202, from an inactivated state to an activated state - wherein in the activated state, the ultrasound transducer / element(s) / array(s) emit(s) and direct(s) focused ultrasound waves onto a target region, and in the inactivated state, the ultrasound transducer / element(s) / array(s) do(es) not emit ultrasound waves.

[0087] In an embodiment, step 1306 comprises responding to a determination that the contact states satisfy a predefined contact state threshold requirement, by switching the entire primary ultrasound transducer 2022 or the entire active surface region 2023 of the primary ultrasound transducer 2022 from a deactivated state to an activated state. In another embodiment, step 1306 comprises responding to a determination that the contact states corresponding to a sub-set of contact sensors disposed within the probe assembly satisfy a predefined contact state threshold requirement, by selectively (i) switching from a deactivated state to an activated state for one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors within the sub-set of contact sensors that satisfy a predefined contact state threshold requirement — wherein in the activated state said one or more ultrasound transducer elements 2033 emit ultrasound waves, and (ii) maintaining in (or switching to) a deactivated state, one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors that do not satisfy the predefined contact state threshold requirement — wherein in the deactivated state said deactivated one or more ultrasound transducer elements 2033 do not emit ultrasound waves. By selectively activating and / or deactivating individual ultrasound transducer elements 2033 based on determined contact states corresponding to contact sensors in the vicinity of said individual ultrasound transducer elements 2033, the method enables steerable or selective activation of only specific portions of the primary ultrasound transducer 2022 that are sufficiently or properly in contact with a subject’s anatomy, while deactivating portions of the primary ultrasound transducer 2022 that have insufficient contact with (and / or air gaps separating) a surface of the subject’s anatomy.

[0088] Figure 14 illustrates a method for contact based activation state control in focused ultrasound based therapy, diagnosis or procedures in accordance with the teachings of the present invention. In an embodiment, the method of Figure 14 may be implemented through a probe assembly 202 configured in accordance with the embodiments described in connection with any one of Figures 8 to 10 hereinabove.

[0089] Step 1402 comprises receiving signal(s) from a set of contact sensors provided within the probe assembly 202. The set of contact sensors may comprise one or more contact sensors 2027, 2031, 2037, disposed within the probe assembly — preferably in locations that are outside of an active surface region 2023 of a primary ultrasound transducer 2022. The signal(s) received from said set of contact sensors may comprise electrical signal(s) representing a contact state or a contact event detected by one or more contact sensors within the set of contact sensors. The signal(s) may be received at a computing device, processor, interface or controller configured to receive signal(s) from contact sensors disposed within probe assembly 202. [0090] Step 1404 comprises determining contact states for each contact sensor within the set of contact sensors, based on signal(s) received from said contact sensors. The determination at step 1404 may be implemented at the computing device, processor, interface or controller at which the signal(s) from contact sensors disposed within probe assembly 202 are received. In an embodiment, each contact state determined at step 1404 may comprise one of (i) a state wherein the corresponding contact sensor is in contact with a surface positioned adjacent to said one or more contact sensors (i.e. a positive contact state) and (ii) a state wherein the corresponding contact sensor is not in contact with any surface (i.e. a negative contact state).

[0091] The determined contact states (or the set of determined contact states corresponding to the set of contact sensors) are compared against a predefined contact state threshold requirement (i.e. a predefined set of contact state rules) to determine whether a primary ultrasound transducer 2022 (or specific regions thereof) is sufficiently or properly in contact with a surface of a subject’s anatomy or with a surface of a region-of-interest on the subject’s anatomy. In an embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, at which (or above which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered sufficiently or properly in contact with an surface of a subject’s anatomy orwith a surface of a region-of-interest on the subject’s anatomy. In another embodiment, the contact state threshold requirement may comprise a defined number of contact sensors that return signals establishing a positive contact state, below which (or at which) the primary ultrasound transducer 2022 (or specific regions thereof) is considered insufficiently or improperly in contact with a surface of a subject’s anatomy orwith a surface of a region-of-interest on the subject’s anatomy.

[0092] Step 1406 comprises responding to a determination that the contact states do not satisfy a predefined contact state threshold, by switching (i) a primary ultrasound transducer 2022 within the probe assembly 202, or (ii) one or more independently activatable ultrasound transducer elements 2033, transducer element arrays or sectored transducer element arrays within the probe assembly 202 , from an activated state to a deactivated state - wherein in the activated state, the ultrasound transducer / element(s) / array(s) emit(s) and direct(s) focused ultrasound waves onto a target region, and in the deactivated state, the ultrasound transducer / element(s) / array(s) do(es) not emit ultrasound waves.

[0093] In an embodiment, step 1406 comprises responding to a determination that the contact states do not satisfy a predefined contact state threshold requirement, by switching the entire primary ultrasound transducer 2022 or the entire active surface region 2023 of the primary ultrasound transducer 2022 from an activated state to a deactivated state. In another embodiment, step 1306 comprises responding to a determination that the contact states corresponding to a subset of contact sensors disposed within the probe assembly do not satisfy a predefined contact state threshold requirement, by selectively (i) switching from an activated state to a deactivated state for one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors within the sub-set of contact sensors that do not satisfy a predefined contact state threshold requirement — wherein in the deactivated state said one or more ultrasound transducer elements 2033 do not emit ultrasound waves, and (ii) maintaining in (or switching to) an activated state, one or more ultrasound transducer elements 2033 that are located in a defined vicinity of one or more contact sensors that satisfy the predefined contact state threshold requirement — wherein in the activated state said activated one or more ultrasound transducer elements 2033 emit ultrasound waves. By selectively activating and / or deactivating individual ultrasound transducer elements 2033 based on determined contact states corresponding to contact sensors in the vicinity of said individual ultrasound transducer elements 2033, the method enables steerable or selective activation of only specific portions of the primary ultrasound transducer 2022 that are sufficiently or properly in contact with a subject’s anatomy, while deactivating portions of the primary ultrasound transducer 2022 that have insufficient contact with (and / or air gaps separating) a surface of the subject’s anatomy.

[0094] Figure 15 illustrates a transducer apparatus configured for contact based activation state control in accordance with the teachings of the present invention.

[0095] Transducer apparatus 1500 comprises a probe assembly 1502. Probe assembly 1502 comprises one or more ultrasound transducer(s) 15022 (in an embodiment comprising at least a primary ultrasound transducer and optionally one or more additional ultrasound transducers) and one or more contact sensors 15024. At least one ultrasound transducer of the one or more ultrasound transducer(s) 15022 is capable of delivering ultrasound waves for perturbing or fractionating the tissue mass or for implementing boiling histotripsy. In an embodiment the ultrasound transducer 15022 is a focused ultrasound transducer. Ultrasound transducer(s) 15022 may additionally include at least one additional ultrasound transducer. In one embodiment, the at least one additional ultrasound transducer is a second ultrasound transducer. In another embodiment, the at least one additional ultrasound transducer is a passive cavitation detector. In a particular embodiment, the additional ultrasound transducer is positioned coaxially relative to the primary ultrasound transducer, within probe assembly 202. In one embodiment, probe assembly 1502 may include both of a second ultrasound transducer and a passive cavitation detector positioned coaxially relative to the primary ultrasound transducer. In an embodiment, probe assembly 1502 may only include a primary ultrasound transducer without either of a second ultrasound transducer and a passive cavitation detector.

[0096] Contact sensors 15024 may comprise any type of sensor capable of being used to identify contact or a lack of contact with another surface, and byway of non -limiting examples each contact sensor 15024 may comprise any of a pressure sensor, a strain gauge, a capacitive sensor, a piezo electric sensor, pressure sensor, an ultrasonic sensor, an acoustic sensor, a resistance sensor (in particular for measuring the body resistance), an electromyography sensor, a near infrared spectroscopy (NIRS) sensor, or any other sensor that is capable of determining whether said sensor is in contact with an adjacent surface, or even more particularly whether said sensor is in contact with an anatomical surface of a subject.

[0097] Transducer apparatus 1500 additionally includes a probe assembly holder 1504 — comprising a holder for, or an assembly for holding probe assembly 1502. In an embodiment, probe assembly holder 1504 may comprise a casing or housing within which the primary ultrasound transducer and optionally the at least one additional ultrasound transducer are either partially or wholly housed coaxially relative to each other. In a particular embodiment the probe assembly holder 1504 comprises a housing configured to house both of a primary ultrasound transducer(s) and an additional ultrasound transducer, in a manner wherein the additional ultrasound transducer is disposed partially or wholly within a cavity or hole formed along the central axis of the primary ultrasound transducer.

[0098] Probe assembly holder 1504 is affixed to or coupled with probe manipulation assembly 1506. Probe manipulation assembly 1506 comprises an assembly configured to enable probe assembly 1502 to be moved, positioned or manipulated along or about the x, y and / or z axes. In certain embodiments, probe manipulation assembly 1506 comprises an assembly configured to confer on probe assembly 1502, any of 3, 4, 5 or 6 degrees of freedom. In an embodiment, probe manipulation assembly 1506 comprises any of (i) a linear stage exhibiting translation about a single axis, (ii) a motion stage configured for translation about two perpendicular axes, (iii) a motion stage configured for translation about three perpendicular axes, (iv) an articulated arm assembly comprising a plurality of interconnected arms, wherein one or more arms is / are pivotably interconnected to at least other arm in a manner that enables manipulation of probe assembly 1502 along or about the x, y and / or z axes, or to confer on probe assembly 1502, any of 3, 4, 5 or 6 degrees of freedom, (v) an articulated arm assembly comprising a first arm and a second arm that are pivotably interconnected, wherein the articulated arm assembly is configured to enable manipulation of probe assembly 1502 along or about the x, y and / or z axes, or to confer on probe assembly 1502, any of 3, 4, 5 or 6 degrees of freedom, and (vi) a robotic arm assembly configured to enable robotic manipulation of probe assembly 1502 along or about the x, y and / or z axes, or to confer on probe assembly 1502, any of 3, 4, 5 or 6 degrees of freedom. Probe manipulation assembly 1506 may be controlled either manually or through a computer application program implemented through a computer or a processor, or through a specifically configured controller. The probe manipulation assembly 1506 may be controlled either through wired or wireless controllers — enabling a physician or operator to perform gross positioning of probe assembly 1502 (or the transducer(s) therewithin) optimally relative to a subject’s anatomy or relative to a region-of-interest / tissue-of-interest within a subject’s anatomy.

[0099] Transducer apparatus 1500 may additionally include signal transmission infrastructure 1508 comprising a bus or interconnections between one or more components of transducer apparatus 1500 and / or between transducer apparatus 1500 and one or more components of system 100 — to enable signalling or transmitting and receiving of signals therebetween.

[00100] Transducer apparatus 1500 also includes a processor 1510 configured to implement one of more method functionalities that have been previously described in connection with the methods of any of Figures 11 to 14.

[00101] Transducer apparatus 1500 includes a processor implemented contact state determination controller 1512 configured to implement the step of contact state determination as described in connection with any of steps 1104, 1204, 1304 and I or 1404 of Figures 11, 12, 13 and 14 respectively.

[00102] Transducer apparatus 1500 includes a processor implemented contact state evaluation controller 1514 configured to evaluate whether one or more contact states determined by contact state determination controller 1512 satisfy a predefined contact state threshold — in the manner described hereinabove in connection with the methods of any of Figures 11 to 14. [00103] Transducer apparatus 1500 includes a processor implemented transducer state controller 1516 configured to control activation / deactivation states of a primary ultrasound transducer or of one or more ultrasound transducer elements or element arrays within the primary ultrasound transducer, as described in connection with any of steps 1106, 1206, 1306 and / or 1406 of Figures 11, 12, 13 and 14 respectively.

[00104] In an embodiment, the present invention provides a transducer apparatus for focused ultrasound based tissue intervention. The transducer apparatus comprises a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly.

[00105] The probe assembly comprises a primary ultrasound transducer comprising one or more ultrasound transducer elements. The probe assembly also comprises a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state.

[00106] The transducer state controller within the transducer apparatus may be configured to selectively change an activation state of at least one ultrasound transducer element within the primary ultrasound transducer based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

[00107] In an embodiment of the transducer apparatus, the transducer state controller is configured to activate at least one transducer element within the primary ultrasound transducer in response to determining that the identified contact states satisfy a predetermined contact state threshold requirement.

[00108] In another embodiment of the transducer apparatus, the transducer controller is configured to (i) selectively activate at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element satisfies a predetermined contact state threshold requirement, and (ii) maintain in a deactivated state, or selectively deactivate, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element does not satisfy a predetermined contact state threshold requirement.

[00109] In a particular embodiment of the transducer apparatus, the transducer state controller is configured to deactivate at least one transducer element within the primary ultrasound transducer in response to determining that the identified contact states do not satisfy a predetermined contact state threshold requirement.

[00110] In a further embodiment of the transducer apparatus, the transducer state controller is configured to (i) selectively deactivate at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element does not satisfy a predetermined contact state threshold requirement, and (ii) maintain in an activated state, or selectively activate, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element satisfies a predetermined contact state threshold requirement.

[00111] In an embodiment of the transducer apparatus, the primary ultrasound transducer comprises a defined active surface region configured for emission of ultrasound waves. One or more contact sensors within the set of contact sensors are located within an inactive surface region within the probe assembly, wherein the inactive surface region is distinct from the active surface region of the primary ultrasound transducer, and wherein the inactive surface region excludes ultrasound wave emission capability.

[00112] The transducer apparatus may be configured such that, the one or more contact sensors within the set of contact sensors are located outside an external periphery of the active surface region, or are located between a central cavity formed within the primary ultrasound transducer and the active surface region, or are located between adjacent peripheral boundaries of adjoiningly positioned ultrasound transducer elements within the primary ultrasound transducer.

[00113] In a specific embodiment of the transducer apparatus, the primary ultrasound transducer is configured for derated acoustic intensity (ISPTA) of 720 mW/ cm2 or above, wherein ISPTA is intensity spatial peak temporal average and either MI> 1.9, wherein MI is mechanical index, or derated ISPPA > 190 W/ cm2, wherein ISPPA is intensity spatial peak pulse average.

[00114] In another embodiment, the present invention provides a method for focused ultrasound based tissue intervention implemented through a transducer apparatus. The transducer apparatus comprises a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly. The probe assembly includes a primary ultrasound transducer comprising one or more ultrasound transducer elements and a set of contact sensors. Each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state. The method comprises the steps of (i) receiving signal(s) from the set of contact sensors, (ii) determining contact states for each contact sensor within the set of contact sensors, wherein determination of the contact states is based on signal(s) received from said contact sensors, (iii) comparing the determined contact states against a predefined contact state threshold requirement, and (iv) selectively changing an activation state of at least one ultrasound transducer element within the primary ultrasound transducer, based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

[00115] In an embodiment of the method, at least one transducer element within the primary ultrasound transducer is activated in response to determining that the identified contact states satisfy a predetermined contact state threshold requirement.

[00116] In another embodiment, the method comprises (i) selectively activating at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element satisfies a predetermined contact state threshold requirement, and (ii) maintaining in a deactivated state, or selectively deactivating, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element does not satisfy a predetermined contact state threshold requirement.

[00117] The method may, in an embodiment, comprise deactivating at least one transducer element within the primary ultrasound transducer in response to determining that the identified contact states do not satisfy a predetermined contact state threshold requirement.

[00118] In another embodiment, the method may comprise (i) selectively deactivating at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element does not satisfy a predetermined contact state threshold requirement, and (ii) maintaining in an activated state, or selectively activating, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element satisfies a predetermined contact state threshold requirement.

[00119] In an embodiment of the method, (i) the primary ultrasound transducer comprises a defined active surface region configured for emission of ultrasound waves, and (ii) one or more contact sensors within the set of contact sensors are located within an inactive surface region within the probe assembly, wherein the inactive surface region is distinct from the active surface region of the primary ultrasound transducer, and wherein the inactive surface region excludes ultrasound wave emission capability.

[00120] In a particular embodiment of the method, the one or more contact sensors within the set of contact sensors are located outside an external periphery of the active surface region, or are located between a central cavity formed within the primary ultrasound transducer and the active surface region, or are located between adjacent peripheral boundaries of adjoiningly positioned ultrasound transducer elements within the primary ultrasound transducer.

[00121] In an embodiment of the method, the primary ultrasound transducer is operated at derated acoustic intensity (ISPTA) of 720 mW/cm2 or above, wherein ISPTA is intensity spatial peak temporal average, and either MI>1.9, wherein MI is mechanical index, or derated ISPPA > 190 W/ cm2, wherein ISPPA is intensity spatial peak pulse average.

[00122] The invention also provides a computer program product for focused ultrasound based tissue intervention implemented through a transducer apparatus. The transducer apparatus comprises a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly. The probe assembly includes a primary ultrasound transducer comprising one or more ultrasound transducer elements and a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state. The computer program product comprises a non-transitory computer usable medium having computer readable program code embodied therein, the computer readable program code comprising instructions for implementing at a processor, the steps of (i) receiving signal(s) from the set of contact sensors, (ii) determining contact states for each contact sensor within the set of contact sensors, wherein determination of the contact states is based on signal(s) received from said contact sensors, (iii) comparing the determined contact states against a predefined contact state threshold requirement, and (iv) selectively changing an activation state of at least one ultrasound transducer element within the primary ultrasound transducer, based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

[00123] The systems, apparatuses and methods described above enables determinations whether an ultrasound transducer has been placed flush against a region of interest on a subject’s anatomy, enables prevention of delivery of ultrasound therapy through improperly positioned ultrasound transducers, and elimination of air gaps, as well as the attendant risks and injuries or tissue trauma that typically can arise out of improperly placed ultrasound transducers in high intensity focused ultrasound applications.

[00124] Figure 16 illustrates an exemplary system 1600 for implementing the present invention. The illustrated system 1600 comprises computer system 1602 which in turn comprises one or more processors 1604 and at least one memory 1606. Processor 1604 is configured to execute program instructions - and may be a real processor or a virtual processor. It will be understood that computer system 1602 does not suggest any limitation as to scope of use or functionality of described embodiments. The computer system 1602 may include, but is not be limited to, one or more of a general-purpose computer, a programmed microprocessor, a microcontroller, an integrated circuit, and other devices or arrangements of devices that are capable of implementing the steps that constitute the method of the present invention. Exemplary embodiments of a computer system 1602 in accordance with the present invention may include one or more servers, desktops, laptops, tablets, smart phones, mobile phones, mobile communication devices, tablets, phablets and personal digital assistants. In an embodiment of the present invention, the memory 1606 may store software for implementing various embodiments of the present invention. The computer system 1602 may have additional components. For example, the computer system 1602 may include one or more communication channels 1608, one or more input devices 1610, one or more output devices 1612, and storage 1614. An interconnection mechanism (not shown) such as a bus, controller, or network, interconnects the components of the computer system 1602. In various embodiments of the present invention, operating system software (not shown) provides an operating environment for various softwares executing in the computer system 1602 using a processor 1604, and manages different functionalities of the components of the computer system 1602.

[00125] The communication channel(s) 1608 allow communication over a communication medium to various other computing entities. The communication medium provides information such as program instructions, or other data in a communication media. The communication media includes, but is not limited to, wired or wireless methodologies implemented with an electrical, optical, RF, infrared, acoustic, microwave, Bluetooth or other transmission media.

[00126] The input device(s) 1610 may include, but is not limited to, a touch screen, a keyboard, mouse, pen, joystick, trackball, a voice device, a scanning device, or any another device that is capable of providing input to the computer system 1602. In an embodiment of the present invention, the input device (s) 1610 may be a sound card or similar device that accepts audio input in analog or digital form. The output device(s) 1612 may include, but not be limited to, a user interface on CRT, LCD, LED display, or any other display associated with any of servers, desktops, laptops, tablets, smart phones, mobile phones, mobile communication devices, tablets, phablets and personal digital assistants, printer, speaker, CD/DVD writer, or any other device that provides output from the computer system 1602.

[00127] The storage 1614 may include, but not be limited to, magnetic disks, magnetic tapes, CD-ROMs, CD-RWs, DVDs, any types of computer memory, magnetic stripes, smart cards, printed barcodes or any other transitory or non-transitory medium which can be used to store information and can be accessed by the computer system 1602. In various embodiments of the present invention, the storage 1614 may contain program instructions for implementing any of the described embodiments.

[00128] In an embodiment of the present invention, the computer system 1602 is part of a distributed network or a part of a set of available cloud resources.

[00129] The present invention may be implemented in numerous ways including as a system, a method, or a computer program product such as a computer readable storage medium or a computer network wherein programming instructions are communicated from a remote location.

[00130] The present invention may suitably be embodied as a computer program product for use with the computer system 1602. The method described herein is typically implemented as a computer program product, comprising a set of program instructions that is executed by the computer system 1602 or any other similar device. The set of program instructions may be a series of computer readable codes stored on a tangible medium, such as a computer readable storage medium (storage 1614), for example, diskette, CD-ROM, ROM, flash drives or hard disk, or transmittable to the computer system 1602, via a modem or other interface device, over either a tangible medium, including but not limited to optical or analogue communications channel(s) 1608. The implementation of the invention as a computer program product may be in an intangible form using wireless techniques, including but not limited to microwave, infrared, Bluetooth or other transmission techniques. These instructions can be preloaded into a system or recorded on a storage medium such as a CD-ROM, or made available for downloading over a network such as the Internet or a mobile telephone network. The series of computer readable instructions may embody all or part of the functionality previously described herein.

[00131] While the exemplary embodiments of the present invention are described and illustrated herein, it will be appreciated that they are merely illustrative. It will be understood by those skilled in the art that various modifications in form and detail may be made therein without departing from or offending the scope of the invention as defined by the appended claims. Additionally, the invention illustratively disclose herein suitably may be practiced in the absence of any element which is not specifically disclosed herein — and in a particular embodiment specifically contemplated, is intended to be practiced in the absence of any element which is not specifically disclosed herein.

Claims

We claim:

1. A transducer apparatus for focused ultrasound based tissue intervention, comprising: a probe assembly; a probe manipulation assembly; a processor implemented transducer state controller; and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly; wherein the probe assembly comprises: a primary ultrasound transducer comprising one or more ultrasound transducer elements; and a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state; and wherein the transducer state controller is configured to selectively change an activation state of at least one ultrasound transducer element within the primary ultrasound transducer based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

2. The transducer apparatus as claimed in claim 1, wherein the transducer state controller is configured to activate at least one transducer element within the primary ultrasound transducer in response to determining that the identified contact states satisfy a predetermined contact state threshold requirement.

3. The transducer apparatus as claimed in claim 1, wherein the transducer controller is configured to: selectively activate at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element satisfies a predetermined contact state threshold requirement; and maintain in a deactivated state, or selectively deactivate, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element does not satisfy a predetermined contact state threshold requirement.

4. The transducer apparatus as claimed in claim 1, wherein the transducer state controller is configured to deactivate at least one transducer element within the primary ultrasound transducer in response to determining that the identified contact states do not satisfy a predetermined contact state threshold requirement.

5. The transducer apparatus as claimed in claim 4, wherein the transducer state controller is configured to: selectively deactivate at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element does not satisfy a predetermined contact state threshold requirement; and maintain in an activated state, or selectively activate, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element satisfies a predetermined contact state threshold requirement.

6. The transducer apparatus as claimed in claim 1, wherein: the primary ultrasound transducer comprises a defined active surface region configured for emission of ultrasound waves; and one or more contact sensors within the set of contact sensors are located within an inactive surface region within the probe assembly, wherein the inactive surface region is distinct from the active surface region of the primary ultrasound transducer, and wherein the inactive surface region excludes ultrasound wave emission capability.

7. The transducer apparatus as claimed in claim 6, wherein the one or more contact sensors within the set of contact sensors are located: outside an external periphery of the active surface region; between a central cavity formed within the primary ultrasound transducer and the active surface region; or between adjacent peripheral boundaries of adjoiningly positioned ultrasound transducer elements within the primary ultrasound transducer.

8. The transducer apparatus as claimed in claim 1, wherein the primary ultrasound transducer is configured for: derated acoustic intensity (ISPTA) of 720 mW/cm² or above, wherein ISPTA is intensity spatial peak temporal average; and either MI>1.9, wherein MI is mechanical index, or derated ISPPA > 190 W/cm², wherein ISPPA is intensity spatial peak pulse average.

9. A method for focused ultrasound based tissue intervention implemented through a transducer apparatus, comprising a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly, wherein the probe assembly includes a primary ultrasound transducer comprising one or more ultrasound transducer elements and a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state, the method comprising the steps of: receiving signal(s) from the set of contact sensors; determining contact states for each contact sensor within the set of contact sensors, wherein determination of the contact states is based on signal(s) received from said contact sensors; comparing the determined contact states against a predefined contact state threshold requirement; and selectively changing an activation state of at least one ultrasound transducer element within the primary ultrasound transducer, based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.

10. The method as claimed in claim 9, wherein the at least one transducer element within the primary ultrasound transducer is activated in response to determining that the identified contact states satisfy a predetermined contact state threshold requirement.

11. The method as claimed in claim 9, comprising: selectively activating at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element satisfies a predetermined contact state threshold requirement; and maintaining in a deactivated state, or selectively deactivating, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element does not satisfy a predetermined contact state threshold requirement.

12. The method as claimed in claim 9, comprising deactivating at least one transducer element within the primary ultrasound transducer in response to determining that the identified contact states do not satisfy a predetermined contact state threshold requirement.

13. The method as claimed in claim 12, comprising: selectively deactivating at least a first transducer element within the primary ultrasound transducer in response to determining that an identified contact state corresponding to a first contact sensor associated with said first transducer element does not satisfy a predetermined contact state threshold requirement; and maintaining in an activated state, or selectively activating, at least a second transducer element within the primary ultrasound transducer, in response to determining that an identified contact state corresponding to a second contact sensor associated with said second transducer element satisfies a predetermined contact state threshold requirement.

14. The method as claimed in claim 9, wherein: the primary ultrasound transducer comprises a defined active surface region configured for emission of ultrasound waves; and one or more contact sensors within the set of contact sensors are located within an inactive surface region within the probe assembly, wherein the inactive surface region is distinct from the active surface region of the primary ultrasound transducer, and wherein the inactive surface region excludes ultrasound wave emission capability.

15. The method as claimed in claim 14, wherein the one or more contact sensors within the set of contact sensors are located: outside an external periphery of the active surface region; between a central cavity formed within the primary ultrasound transducer and the active surface region; or between adjacent peripheral boundaries of adjoiningly positioned ultrasound transducer elements within the primary ultrasound transducer.

16. The method as claimed in claim 9, wherein the primary ultrasound transducer is operated at: derated acoustic intensity (ISPTA) of 720 mW/cm² or above, wherein ISPTA is intensity spatial peak temporal average; and either MI>1.9, wherein MI is mechanical index, or derated ISPPA > 190 W/cm², wherein ISPPA is intensity spatial peak pulse average.

17. A computer program product for focused ultrasound based tissue intervention implemented through a transducer apparatus, comprising a probe assembly, a probe manipulation assembly, a processor implemented transducer state controller, and a probe assembly holder configured to couple the probe assembly and the probe manipulation assembly, wherein the probe assembly includes a primary ultrasound transducer comprising one or more ultrasound transducer elements and a set of contact sensors, wherein each contact sensor within the set of contact sensors is configured to generate a signal identifying a contact state, the computer program product comprising a non-transitory computer usable medium having computer readable program code embodied therein, the computer readable program code comprising instructions for implementing at a processor, the steps of: receiving signal(s) from the set of contact sensors; determining contact states for each contact sensor within the set of contact sensors, wherein determination of the contact states is based on signal(s) received from said contact sensors; comparing the determined contact states against a predefined contact state threshold requirement; and selectively changing an activation state of at least one ultrasound transducer element within the primary ultrasound transducer, based on one or more identified contact states that have been identified based on signal(s) received from the set of contact sensors.