Device and method for ultrasound treatment of biological tissue

1 . A medical device for applying heat-based tissue treatment to an individual's body part, the device comprising an applicator carrying a transducer arrangement configured and controllably operable to perform a treatment session on at least one region of interest in tissue to achieve a desired treatment effect at each of said at least one region of interest; wherein:

the applicator is configured to define a substantially U-shaped surface presenting a U-shaped interface region for attachment with the body part along said U-shaped surface such that each of the at least one region of interest is located between opposite arms of said U-shaped interface region, thereby enabling attachment of tissue being treated in a cavity defined by the U-shaped interface region;

the transducer arrangement is configured and controllably operable to perform a treatment session on each of said at least one region of interest by delivering unfocused directional radiation comprising heating radiation towards each of said at least one region of interest;

the transducer arrangement comprises first and second opposing ultrasound transducer-assemblies defining, respectively, first and second opposing ultrasound-transceiving surfaces located at the opposite arms of the U-shaped interface region, such that each of the first and second ultrasound transducer assemblies has respective forward-facing transceiving surface by which it faces the other opposing transceiving surface via the region between the opposite arms of the U-shaped interface region of the applicator;

said first and second ultrasound transducer-assemblies are configured operable to generate the first and second ultrasound radiations of respectively first and second different frequencies selected to avoid creation of or significantly reduce a standing wave effect and provide homogeneous temperature along the region of interest during the treatment session; and

the first and second ultrasound transducer-assemblies are configured to transmit the unfocused directional ultrasound radiation in opposite directions, such that the unfocused directional ultrasound radiation propagates from one of said ultrasound-transceiving surfaces to the other opposing ultrasound-transceiving surface and is detected at the other opposing ultrasound-transceiving surface, providing that measured data corresponding to the detected ultrasound radiation is indicative of time-of-flight data of the ultrasound radiation between the first and second opposing ultrasound-transceiving surfaces and therefore indicative of a temperature of the region of interest between said first and second opposing ultrasound-transceiving surfaces and indicative of attachment of the tissue to the interface region, said transducer arrangement being thereby configured and controllably operable to perform the treatment session on each of said at least one region of interest, and configured and controllably operable to perform a control session comprising control of the temperature and attachment during the treatment session based on said measured data.

2 . The medical device according to claim 1 , wherein said first and second opposing ultrasound transducer-assemblies are configured and operable to generate said heating radiation, said first and second ultrasound transducer-assemblies being configured to generate directional first and second ultrasound heating radiations propagating in the opposite directions along the substantially coinciding first and second axes towards each of the at least one region of interest in the tissue being engaged between said opposite arms of the interface region.

3 . The medical device according to claim 1 , further comprising at least one of the following:

a cooling assembly configured and controllably operable to perform cooling of the interface region during the treatment session;

a control unit configured and operable to control operation of said applicator to maintain predetermined temperature pattern in the tissue during the treatment session;

a temperature control circuitry for monitoring temperature of said at least one region of interest; and

an attachment control circuitry configured and operable to monitor acoustic contact between the tissue and at least a part of said interface region and control operation of the transducer arrangement accordingly.

4 . The medical device according to claim 3 , comprising the temperature control circuitry and the attachment control circuitry, wherein:

said temperature control circuitry is responsive to said measured data indicative of the detected ultrasound radiation from the tissue to extract from said measured data at least one of an average temperature of the region of interest at respective location in the tissue; and

said attachment control circuitry is responsive to said measured data indicative of the detected ultrasound radiation from the tissue and at least a part of said interface region to control operation of the transducer arrangement accordingly.

5 . The medical device according to claim 4 , wherein said applicator further comprises at least one temperature sensor located in vicinity of the interface region and configured and operable to provide sensing data indicative of temperature of surface tissue regions.

6 . The medical device according to claim 3 , comprising the cooling assembly configured and controllably operable to perform cooling of the interface region during the treatment session and the temperature control circuitry for monitoring temperature of said at least one region of interest, the device being characterized by at least one of the following:

said temperature control circuitry is responsive to measured data indicative of an operative electric current of the cooling assembly required to cool the interface region to provide a predetermined temperature of tissue surface at the interface region to apply, based on said measured data, model-based processing utilizing thermal properties of a biological tissue under treatment and determine an average temperature of said tissue;

said control unit is configured and operable to control the operation of said ultrasound transducer arrangement and said cooling assembly to provide maximum temperature of about 30 degrees Celsius at said interface region; and

said control unit is configured and operable to control the operation of said ultrasound transducer arrangement and said cooling assembly to maintain temperature of the region of interest at deep location with respect to the region of interest to be at least 45 degrees Celsius during the treatment session.

7 . The medical device according to claim 3 , comprising a temperature control circuitry for monitoring temperature of said at least one region of interest, wherein:

said control unit is configured and operable to control the operation of said ultrasound transducer arrangement and said cooling assembly to maintain temperature of the region of interest at deep location with respect to the region of interest to be at least 45 degrees Celsius during the treatment session, the control unit being configured and operable to maintain said temperature of the region of interest to be in a range between 45 degrees Celsius and 55 degrees Celsius by modifying at least one operational parameter of said transducer arrangement, and

said at least one parameter includes at least one of power-level and duty cycle of the ultrasound radiation.

8 . The medical device according to claim 3 , characterized by at least one of the following:

the cooling assembly comprises one or more Peltier cooling components;

a distance between the first and second substantially flat ultrasound-transceiving surfaces at the arms of the U-shaped interface region is in a range of 2-7 cm; and

each of the first and second substantially flat ultrasound-transceiving surfaces has a surface area of at least 4 cm 2 .

9 . The medical device according to claim 1 , having one of the following configurations:

(i)) said applicator is configured such that its surface comprising said interface region is flexible and foldable such that it is adapted to define said substantially U-shaped interface region; and

(ii) a surface of said applicator comprising the U-shaped interface region is rigid.

10 . The medical device according to claim 1 , wherein the measured data is indicative of the time-of-flight data of said unfocused directional radiation being pulsed ultrasound radiation between the first and second transducer assemblies and thereby corresponds to the time-of-flight of ultrasound radiation through the tissue engaged between the opposite arms of said interface region, thereby enabling real time extraction from the time-of-flight data an average temperature of said region of interest being a deep region with respect to the interface region.

11 . The medical device according to claim 10 , configured and operable to carry out at least one of the following:

(a) utilize calibration data indicative of tissue temperature as a function of a change in the time-of-flight of the ultrasound radiation of a given frequency passing through a given biological tissue, to evaluate, from the measured time-of-flight data, data indicative of an average temperature of the region of interest in the tissue; and

(b) utilize calibration data indicative of acoustic contact of the tissue and the interface region as a function of the time-of-flight of the ultrasound radiation of a given frequency passing through a given biological tissue, to evaluate, from the measured time-of-flight data, data indicative of the acoustic contact.

12 . The medical device claim 1 , having at least one of the following configurations:

the first and second transducer assemblies are configured and controllable to generate the first and second ultrasound radiations of respectively first and second frequencies with a difference between them in a range of 0.5%-20%;

said first and second opposing transducer assemblies comprise, respectively, first and second arrays of independently operable transceiver elements, the ultrasound-transceiving surface of each of said first and second transducer assemblies being defined by respective one of the first and second arrays of spaced-apart surface segments associated with the first and second arrays of the transceiver elements, thereby defining at least two opposing pairs of the ultrasound transceiver elements, each pair being formed by the first and second transceiver elements generating the first and second directional ultrasound radiations propagating along substantially coinciding axes in the opposite directions towards the region of interest in the tissue being engaged between said opposing sides of the interface region;

said transducer arrangement is configured and controllably operable with a time pattern of alternating tissue treatment intervals of the treatment session and intervals of the control session;

said transducer arrangement comprises an additional transducer assembly accommodated to transmit ultrasound radiation through a base portion of the U-shaped interface region;

said transducer arrangement is configured and operable with a pulsed mode during the control session;

the ultrasound transducer arrangement is capable of selectively operating in one of the following operational modes: a continuous wave operational mode of a predetermined duty cycle, and a pulsed operational mode; and

said applicator further comprises first and second temperature sensors configured and operable to measure respective first and second temperatures in vicinity of said arms of the U-shaped interface region and provide corresponding sensing data being indicative of temperature of surface tissue regions.

13 . The medical device according to claim 1 , wherein the first and second transducer assemblies are configured and controllable to generate the first and second ultrasound radiations of respectively first and second frequencies with a difference between them in a range of 0.5%-20%, the first and second frequencies being selected to avoid creation of the standing wave effect and provide homogeneous temperature along the region of interest during the treatment session.

14 . The medical device according to claim 1 , wherein said first and second opposing transducer assemblies comprise, respectively, first and second arrays of independently operable transceiver elements, the ultrasound-transceiving surface of each of said first and second transducer assemblies being defined by respective one of the first and second arrays of spaced-apart surface segments associated with the first and second arrays of the transceiver elements, thereby defining at least two opposing pairs of the ultrasound transceiver elements, each pair being formed by the first and second transceiver elements generating the first and second directional ultrasound radiations propagating along substantially coinciding axes in the opposite directions towards the region of interest in the tissue being engaged between said opposing sides of the interface region, said transducer arrangement being configured and controllably operable to concurrently perform treatment sessions on at least two regions of interest being deep and shallow tissue regions with respect to their locations from the interface region.

15 . The medical device according to claim 1 , wherein said transducer arrangement is configured and controllably operable with a time pattern of alternating tissue treatment intervals of the treatment session and intervals of the control session, the device being characterized by at least one of the following:

the transducer arrangement is configured and controllably operable with a time pattern of alternating tissue treatment intervals of the treatment session and intervals of the control session implemented by, respectively, two different pairs of the opposing transceiver elements;

said control session comprises temperature control of the region of interest being treated based on the detection of the ultrasound radiation passed through the region of interest, enabling real time adjustment of one or more operational parameters of the treatment session;

the control session comprises control of acoustic contact between the interface region and the tissue surface engaged by said interface region, enabling real time adjustment of the treatment session; and

said transducer arrangement is controllably operated with the continuous wave operational mode during said intervals of the treatment session and controllably operated with the pulsed mode during the intervals of the control session.

16 . The medical device according to claim 15 , wherein said transducer arrangement is controllably operated with the continuous wave operational mode during said intervals of the treatment session and controllably operated with the pulsed mode during the intervals of the control session, the device being characterized by at least one of the following:

operational frequency of the ultrasound radiation during the treatment session is in a range of 1 MHz-4 Hz; and

said region of interest being treated is a deep region with respect to the interface region.

17 . The medical device according to claim 1 , wherein said transducer arrangement comprises an additional transducer assembly accommodated to transmit ultrasound radiation through a base portion of the U-shaped interface region, said region of interest being a shallow region with respect to the interface region.

18 . The medical device according to claim 1 , wherein said transducer arrangement is configured and operable with a pulsed mode during the control session, said region of interest being a shallow region with respect to the interface region.

19 . The medical device according to claim 1 , wherein:

said transducer arrangement is characterized by one of the following:

said transducer arrangement comprises an additional transducer assembly accommodated to transmit ultrasound radiation through a base portion of the U-shaped interface region; and

said transducer arrangement is configured and operable with a pulsed mode during the control session;

said region of interest is a shallow region with respect to the interface region; and

operational frequency of the ultrasound radiation during the treatment session is in a range of 4.5 MHz.

20 . The medical device according to claim 1 , wherein said interface region of the applicator has at least one of the following configurations:

said interface region of the applicator has a distal side of a substantially flat surface for contacting tissue being treated and an opposite proximate side carrying one or more elements of the transducer arrangement and one or more elements of the cooling assembly; and

said interface region of the applicator is made of a heat conducting material and is configured to provide substantial impedance matching with impedance of the transducer arrangement, such that the ultrasound radiation passage through said interface region has energy losses not exceeding 10%.

21 . The medical device according to claim 1 , comprising:

an attachment control circuitry configured and operable to monitor acoustic contact between the tissue and at least a part of said interface region and control operation of the transducer arrangement accordingly; and

a tissue attachment mechanism configured and controllably operable by said attachment control circuitry to provide a desired acoustic contact between said at least part of the interface region and the tissue under treatment.

22 . The medical device according to claim 21 , characterized by at least one of the following:

said tissue attachment mechanism comprises a source of negative pressure for urging the tissue towards the interface region of the applicator; and

said attachment control circuitry is configured and operable to selectively increase or decrease a strength of the negative pressure upon identifying, respectively, decrease or increase in a prevailing average temperature of surface of the tissue under treatment.

23 . The medical device according to claim 22 , wherein said attachment control circuitry is configured and operable to increase a strength of the negative pressure upon identifying, from said measured data, an increase in a prevailing average time-of-flight of the detected ultrasound radiation.