Boiling histotripsy methods and systems for uniform volumetric ablation of an object by high-intensity focused ultrasound waves with shocks

Abstract

An example method includes generating an acoustic ultrasound wave that is focused at a focal point. The method further includes sequentially directing the focal point upon distinct portions of an object to form respective shock waves at the distinct portions of the object. The method further includes, via the respective shock waves, causing the distinct portions of the object to boil and form respective vapor cavities. The method further includes causing substantially uniform ablation of a region of the object that comprises the distinct portions. The substantially uniform ablation is caused via interaction of the respective shock waves with the respective vapor cavities. An example ablation system and an example non-transitory computer-readable medium, both related to the example method, are also disclosed.

1 . A method comprising:
 generating an acoustic ultrasound wave that is focused at a focal point;   sequentially directing the focal point upon distinct portions of an object to form respective shock waves at the distinct portions of the object;   via the respective shock waves, causing the distinct portions of the object to boil and form respective vapor cavities; and   causing substantially uniform ablation of a region of the object that comprises the distinct portions, wherein the substantially uniform ablation is caused via interaction of the respective shock waves with the respective vapor cavities .   
     
     
         2 . (canceled) 
     
     
         3 . The method of  claim 1 , wherein the object is a biological tissue within a living organism. 
     
     
         4 . The method of  claim 3 , wherein the biological tissue is selected from a group consisting of a brain tissue, a nerve tissue, a liver tissue, a kidney tissue, a muscle tissue, a fat tissue, a connective tissue, a tumor, a hematoma, an abscess, a lipoma, a diseased tissue, and an undesirable tissue. 
     
     
         5 .- 17 . (canceled) 
     
     
         18 . The method of  claim 1 , wherein a given shock wave of the respective shock waves has a pressure magnitude of at least about 40 MPa at a focus of the given shock wave. 
     
     
         19 . (canceled) 
     
     
         20 . The method of  claim 1 , wherein the acoustic ultrasound wave has an oscillation frequency that is greater than 900 kHz and less than 20 MHz. 
     
     
         21 . (canceled) 
     
     
         22 . The method of  claim 1 , wherein the acoustic ultrasound wave has a duty cycle that is greater than 0.5% and less than 12%. 
     
     
         23 . (canceled) 
     
     
         24 . The method of  claim 1 , wherein the acoustic ultrasound wave has a pulse duration that is greater than 0.1 millisecond and less than or equal to 40 milliseconds. 
     
     
         25 .- 26 . (canceled) 
     
     
         27 . The method of  claim 1 , wherein causing the distinct portions of the object to boil and form the respective vapor cavities comprises (a) causing a given portion of the distinct portions to absorb a given number of pulses of the acoustic ultrasound wave, wherein the given number of pulses is greater than 5 and less than about 200, or (b) initiating boiling of a given portion of the distinct portions of the object while the focal point is directed upon the given portion. 
     
     
         28 .- 31 . (canceled) 
     
     
         32 . The method of  claim 1 , wherein causing substantially uniform ablation of the region of the object that comprises the distinct portions comprises causing liquefaction of a given portion of the distinct portions of the object mechanical ablation of a given portion of the distinct portions of the object, thermal ablation of a given portion of the distinct portions of the object, or combinations thereof. 
     
     
         33 .- 38 . (canceled) 
     
     
         39 . The method of  claim 1 , wherein the distinct portions of the object have a total length of at least 1 centimeter, a total area of at least one square centimeter, and/or a total volume of at least 1 cubic centimeter. 
     
     
         40 .- 41 . (canceled) 
     
     
         42 . The method of  claim 1 , wherein not all portions of the distinct portions of the object are within a common line, and or wherein not all portions of the distinct portions of the object are within a common plane. 
     
     
         43 . (canceled) 
     
     
         44 . The method of  claim 1 , wherein the distinct portions of the object form one or more concentric circles, one or more concentric spheres, and/or a closed loop. 
     
     
         45 .- 46 . (canceled) 
     
     
         47 . The method of an  claim 1 , further comprising:
 determining a trajectory of the distinct portions of the object such that distances between successive portions of the trajectory are maximized,   wherein sequentially directing the focal point upon the distinct portions of the object comprises directing the focal point upon the distinct portions of the object according to the trajectory.   
     
     
         48 . The method of  claim 1 ,
 wherein causing substantially uniform ablation of the region of the object comprises causing the distinct portions of the object to absorb respective amounts of energy from the acoustic ultrasound wave that are substantially equal,   and wherein sequentially directing the focal point upon the distinct portions of the object comprises:
 (a) directing the focal point upon a first portion of the distinct portions, thereby causing the first portion to absorb a first amount of energy of the respective amounts of energy; and 
 thereafter, directing the focal point upon a second portion of the distinct portions, thereby causing the second portion to absorb a second amount of energy of the respective amounts of energy; or 
 (b) directing the focal point upon a first portion of the distinct portions, thereby causing the first portion to absorb a fraction of a first amount of energy of the respective amounts of energy; 
 after causing the first portion to absorb the fraction of the first amount of energy, directing the focal point upon a second portion of the distinct portions, thereby causing the second portion to absorb a fraction of a second amount of energy of the respective amounts of energy; and 
 after causing the second portion to absorb the fraction of the second amount of energy, directing the focal point upon the first portion, thereby causing the first portion to absorb a remainder of the first amount of energy. 
   
     
     
         49 .- 51 . (canceled) 
     
     
         52 . The method of  claim 1 , wherein causing the distinct portions of the object to boil and form respective vapor cavities comprises (a) heating a given volume of the object to at least 100° C., wherein the given volume is greater than 0.1 cubic millimeters and less than 0.5 cubic millimeters, or (b) causing a given portion of the object to boil and form a given vapor cavity having a volume greater than about 3 cubic millimeters and less than about 30 cubic millimeters. 
     
     
         53 .- 54 . (canceled) 
     
     
         55 . The method of  claim 1 , the method further comprising:
 capturing an image of the object; and   determining a trajectory of the distinct portions of the object based on the captured image,   wherein sequentially directing the focal point upon the distinct portions of the object comprises directing the focal point upon the distinct portions of the object according to the trajectory determined based on the captured image.   
     
     
         56 . The method of  claim 55 , the method further comprising:
 determining a size, shape, or location of the object based on the captured image; and   apportioning the object into the distinct portions based on the determined size, shape, or location,   wherein determining the trajectory of the distinct portions of the object based on the captured image comprises determining a trajectory of the apportioned distinct portions.   
     
     
         57 . The method of  claim 1 , further comprising:
 (a) receiving input representing one or more parameters for generating the acoustic ultrasound wave,   wherein the acoustic ultrasound wave is generated according to the received input; and/or   (b) receiving input representing one or more parameters for sequentially directing the focal point upon the distinct portions of the object,   wherein the focal point is sequentially directed upon the distinct portions of the object according to the received input representing the one or more parameters for sequentially directing the focal point.   
     
     
         58 . (canceled) 
     
     
         59 . A non-transitory computer-readable medium storing instructions that, when executed by an ablation system, cause the ablation system to perform the method of  claim 1 . 
     
     
         60 . (canceled) 
     
     
         61 . An ablation system configured to ablate an object, the ablation system comprising:
 one or more processors;   a sensor module configured to collect sensory data from the object during ablation;   an input/output interface configured to receive user input and display an image representing the sensory data;   an ablation module configured to generate an acoustic ultrasound wave and sequentially direct a focal point of the acoustic ultrasound wave upon distinct portions of the object; and   a non-transitory computer-readable medium storing instructions that, when executed by the one or more processors, cause the ablation system to perform the method of  claim 1 .