Interstitial ultrasonic disposable applicator and method for tissue thermal conformal volume ablation and monitoring the same

Abstract

An interstitial ultrasound thermal ablation applicator for conformal treatment of inhomogeneous tumor lesions includes: a body having a longitudinal axis, the body defining a hollow central channel along the longitudinal axis; and a plurality of CMUT array transducers mounted on the body, arranged side by side to form a cylindrical shape, having azimuth plans parallel to a longitudinal axis of the body, each of the plurality of CMUT array transducers having elevation dimensions predetermined to steer emitted ultrasonic waves to obtain a conformal volume treatment of the tumor lesions. An electronic driving method for driving an applicator having multiple independent transducer elements arranged in rows and columns includes: controlling focal parameters of each row and column of transducer elements; and controlling a contribution of each row and column of transducer elements in a manner to provide a conformal ablated volume.

What is claimed is: 
     
         1 . An interstitial ultrasound thermal ablation applicator to be inserted into tumor lesions for conformal treatment of inhomogeneous tumor lesions, comprising:
 a body having a longitudinal needle shape and a longitudinal axis, the body defining a hollow central channel along the longitudinal axis, the hollow central channel serving as a passage for biopsy needles or tools for aspiration of biologic materials or providing in-situ drug delivery; and   a plurality of capacitive micromachined ultrasonic transducer (CMUT) array transducers externally mounted on said body and having on each array a number of separate elementary transducers linearly arranged and said CMUT array transducers are arranged side by side to form a pseudo cylindrical shape and having azimuth plans parallel to the longitudinal axis of the body;   said CMUT array transducers are having predetermined elevation dimension defined for steering emitted ultrasonic energy to obtain a conformal volume treatment of the tumor lesions.   
     
     
         2 . The interstitial ultrasound thermal ablation applicator according to  claim 1 , wherein the CMUT array transducers are wholly covered with electrically insulating protective layers. 
     
     
         3 . The interstitial ultrasound thermal ablation applicator according to  claim 1 , wherein body is made up of organic or mineral material. 
     
     
         4 . The interstitial ultrasound thermal ablation applicator according to  claim 1 , wherein an elevation dimension of said CMUT array transducers are determined to not excess three (3) water equivalent wavelengths. 
     
     
         5 . The interstitial ultrasound thermal ablation applicator according to  claim 1 , wherein a thickness of said CMUT array transducers is provided at less than 100 microns, so as to conform with an external surface of the body. 
     
     
         6 . The interstitial ultrasound thermal ablation applicator according to  claim 1 , further comprising a biocompatible protection film covering the body and the CMUT array transducers. 
     
     
         7 . An interstitial ultrasound thermal ablation applicator to be inserted into tumor lesions for conformal treatment of inhomogeneous tumor lesions, comprising:
 a body having a longitudinal catheter shape and a longitudinal axis;   a plurality of capacitive micromachined ultrasonic transducer (CMUT) array transducers mounted on said body, arranged side by side to form a cylindrical shape, having azimuth plans parallel to the longitudinal axis of the body, each of the said CMUT array transducers having elevation dimensions predetermined to steer emitted ultrasonic energy to control smoothness of a resulting ablation volume; and   at least one integrated sensing device mounted within the transducing area to monitor at least one of the physical/physiological parameters of the surrounding tissue.   
     
     
         8 . The interstitial ultrasound thermal ablation applicator for the treatment of inhomogeneous tumor lesions according to  claim 7 , wherein the integrated sensing device is temperature sensor. 
     
     
         9 . The interstitial ultrasound thermal ablation applicator for the treatment of inhomogeneous tumor lesions according to  claim 7 , wherein the integrated sensing device is a pressure sensor. 
     
     
         10 . The interstitial ultrasound thermal ablation applicator for the treatment of inhomogeneous tumor lesions according to  claim 7 , wherein the integrated sensing device is a gas sensor. 
     
     
         11 . The interstitial ultrasound thermal ablation applicator for the treatment of inhomogeneous tumor lesions according to  claim 7 , wherein the integrated sensing device is a biosensor for detection of enzymes, antibodies or nucleic acids. 
     
     
         12 . The interstitial ultrasound thermal ablation applicator for the treatment of inhomogeneous tumor lesions according to  claim 7 , wherein the integrated sensing device is a laser emitter. 
     
     
         13 . An interstitial ultrasound thermal ablation applicator for treatment of inhomogeneous tumor lesions, comprising:
 a body having a longitudinal catheter shape and a longitudinal axis;   a plurality of capacitive micromachined ultrasonic transducer (CMUT) array transducers mounted on said body, arranged side by side to form a cylindrical shape, having azimuth plans parallel to the longitudinal axis of the body, each of the said CMUT array transducers having elevation dimensions predetermined to steer emitted ultrasonic waves to control smoothness of a resulting ablation volume;   an integrated sensing device for monitoring at least one of a physical/physiological parameters of the surrounding tissue; and   an integrated Lab-on-Chip (LoC) device located within a surface of one of the said CMUT array transducers for in-situ analyzing of tissue.   
     
     
         14 . The interstitial ultrasound thermal ablation applicator for treatment of inhomogeneous tumor lesions according to  claim 13 , wherein the LoC device is a microfluidic device designed for cytometry assays and biological assays. 
     
     
         15 . An electronic driving method for controlling interstitial ultrasound thermal ablation applicator having multiple independent transducer elements arranged in rows and columns and being disposed on a periphery of a cylindrical ultrasound thermal ablation applicator, such method comprising:
 controlling focal parameters of each row and column of transducer elements; and   controlling contribution of each row and column of transducer elements in a manner to provide a conformal ablated volume.   
     
     
         16 . The electronic driving method according to  claim 15 , further comprising:
 shunting electrically adjacent transducer elements two by two in each respective row; and   controlling the transducer elements in columns independently to achieve conformal volume sonication/treatment.   
     
     
         17 . The electronic driving method according to  claim 15 , further comprising:
 shunting together top electrodes of the transducer elements in each respective row, such that all rows are electrically isolated;   shunting together bottom electrodes of the transducer elements in each respective column, such that all columns are electrically isolated; and   activating desired transducer elements by connecting the top electrodes of a selected row and the bottom electrodes of a selected column to a power supply simultaneously to polarize the desired transducer elements located in both the selected rows and the selected columns.   
     
     
         18 . The electronic driving method according to  claim 15 , further comprising:
 shunting together top electrodes of the transducer elements in each respective row, such that all rows are electrically isolated and connecting to an alternative voltage driving system;   shunting together bottom electrodes of the transducer elements in each respective column, such that all columns are electrically isolated; and   connecting to a direct current voltage controller modulating output of a desired transducer element by applying a given DC voltage and AC voltage.   
     
     
         19 . The electronic driving method according to  claim 15 , further comprising:
 activating, by separate DC bias controllers, specific subgroups of elements or arrays of the device, such that a DC bias voltage level delivered to a specific subgroup of elements having a common bottom electrode may be used to modulate acoustic output of the specific subgroup of elements.   
     
     
         20 . The electronic driving method according to  claim 15 , wherein the rows are disposed symmetrically with a symmetry line at a middle of the interstitial ultrasound thermal ablation applicator, wherein the rows are arranged in a position order from P 1  to P N  and Q N  to Q 1 , respectively, around the symmetry line, the method further comprising:
 shunting together top electrodes of the transducer elements forming a row P X  and a row Q X  of same order, such that rows of different orders are electrically isolated;   arranging rows P and rows Q in reverse chronology so as to obtain the last order row P N  adjacent to the last order row Q N  and therefor first order row P 1  and first order Q 1  are located at opposite ends of the interstitial ultrasound thermal ablation applicator;   shunting together bottom electrodes of the transducer elements forming in each respective column, such that all columns are electrically isolated; and   activating a desired transducer element by connecting the top electrodes of a selected row and the bottom electrodes of a selected column to a power supply simultaneously to polarize the desired transducer element located in both the selected row and the selected column.   
     
     
         21 . A method of providing thermal ablation of a tissue region by an interstitial procedure using an interstitial ultrasound thermal ablation applicator comprising a plurality of ultrasonic transducers, comprising:
 inserting and positioning the interstitial ultrasound thermal ablation applicator at a center of one of incriminated tissue and a tumor;   applying electrical actuation individually to the plurality of ultrasonic transducers, each of the plurality of ultrasonic transducers having respective custom focal characteristics;   controlling ultrasonic energy supplied and treatment duration for each of the plurality of ultrasonic transducers to control tissue temperature elevation and distribution;   controlling ultrasonic frequency, phase, and DC bias to control tissue temperature elevation and distribution; and   removing ablated material from a treatment site for assessment.   
     
     
         22 . The method of providing thermal ablation of a tissue region according  claim 21 , the elements integrated on the same applicator allow combining multiple ultrasound beams at various frequencies over a broad continuous spectrum (e.g. 2-30 MHz) for performing conformal thermal ablation. 
     
     
         23 . The method of providing thermal ablation of a tissue region according  claim 21 , the elements integrated on the same applicator allow modulating the frequency, power and phase of the excitation according to the feedback of a treatment monitoring system for performing conformal thermal ablation. 
     
     
         24 . The method of providing thermal ablation of a tissue region according  claim 21 , wherein the procedure is performed under magnetic resonance (MR) scanning to monitor local temperatures. 
     
     
         25 . The method of providing thermal ablation of a tissue region according  claim 21 , wherein the interstitial ultrasound thermal ablation applicator has a catheter shape with a diameter smaller than 4 mm so as to avoid damage to healthy tissue during insertion.