Image-guided thermotherapy based on selective tissue thermal treatment

Abstract

Devices and techniques for thermotherapy based on optical imaging.

What is claimed is: 
     
         1 . A device for thermotherapy, comprising:
 a catheter including a working channel configured for insertion into a passage of a body to reach a target tissue inside the body;   an optical imaging module comprising (1) an imaging optic fiber having a portion inserted into the working channel and (2) an optical probe head coupled to an end of the imaging optic fiber and located inside the working channel, the optical imaging module operable to direct probe light to and collect reflected light from the target tissue in the body through the imaging optic fiber and the optical probe head and to obtain imaging information of the target tissue from the collected reflected light;   a thermotherapy module having a power delivery waveguide having a portion inserted into the working channel to deliver thermal energy to the target tissue;   a control unit that controls the optical imaging module to extract the imaging information from the collected reflected light, to obtain a spatial distribution of diseased locations of the target tissue, and to obtain a temperature map of the target tissue for thermotherapy based on the spatial distribution of the diseased locations of the target tissue, the control unit controlling the thermotherapy module to control a location and an amount of thermal energy delivery to each of the diseased locations based on the temperature map to perform thermotherapy.   
     
     
         2 . The device as in  claim 1 , comprising:
 a liquid cooling unit coupled to the catheter to direct a cooling liquid that cools a surface of the target tissue.   
     
     
         3 . The device as in  claim 1 , wherein the imaging optic fiber is structured to support light in a first propagation mode and a second, different propagation mode, and the optical imaging module includes:
 a light source to produce the probe light, wherein the imaging optic fiber receives and guides the probe light in the first propagation mode,   wherein the optical probe head is coupled to the imaging optic fiber to receive the light from the imaging optic fiber and to reflect a first portion of the light back to the imaging optic fiber in the first propagation mode and direct a second portion of the light to a target location of the target tissue, the probe head collecting reflection of the second portion from the target location and exporting to the imaging optic fiber the reflection as a reflected second portion in the second propagation mode;   an optical differential delay unit to produce and control a relative delay between the reflected first portion and the reflected second portion received from the imaging optic fiber in response to a control signal;   a detection module to receive the reflected first portion and the reflected second portion from the imaging optic fiber and to extract information of the target area carried by the reflected second portion; and   an imaging control unit, which produces the control signal to the optical differential delay unit, to set the relative delay at two different bias values to select a layer of material inside the target area to measure an optical absorption of the selected layer.   
     
     
         4 . The device as in  claim 3 , wherein the detection module comprises:
 an optical device to direct light in the first propagation mode along a first optical path and light in the second propagation mode along a second, different optical path;   a first optical element in the first optical path to separate light into a first set of different beams at different wavelengths;   a plurality of first light detectors to respectively receive and detect the first set of different beams from the first optical element;   a second optical element in the second optical path to separate light into a second set of different beams at the different wavelengths; and   a plurality of second light detectors to respectively receive and detect the second set of different beams from the second optical element.   
     
     
         5 . The device as in  claim 4 , wherein the first and second optical elements are optical gratings. 
     
     
         6 . The device as in  claim 3 , wherein the detection module comprises a digital signal processor to process information of the target area in the reflected second portion and to generate spectral absorbance data of the target area. 
     
     
         7 . The device as in  claim 3 , wherein the optical differential delay unit comprises:
 a mode splitting unit to separate received light into a first beam in the first propagation mode and a second beam in the second propagation mode; and   a variable optical delay element in one of the first and the second beams to adjust an optical delay between the first and the second beams in response to the control signal.   
     
     
         8 . The device as in  claim 3 , wherein the first and second propagation modes are two orthogonal polarization modes supported by the probe optic fiber, and wherein the detection module comprises:
 an optical detector; and   an optical polarizer to receive and mix the reflected first and second portions to produce an optical output to the optical detector.   
     
     
         9 . The device as in  claim 3 , wherein the optical imaging module further comprises:
 a plurality of light sources emitting light at different wavelength bands centered at different wavelengths as the probe light into the probe optic fiber, wherein the optical probe head reflects a first portion of the probe light back to the imaging optic fiber in the first propagation mode and directs a second portion of the probe light to the target area, and wherein the probe head collects reflection of the second portion from the target area and exports to the imaging optic fiber the reflection as a reflected second portion in a second propagation mode different from the first propagation mode;   an optical differential delay unit to produce and control a relative delay between the reflected first portion and the reflected second portion received from the single waveguide in response to a control signal;   a detection module to receive the reflected first portion and the reflected second portion and to extract information of the target area carried by the reflected second portion; and   a probe control unit, which produces the control signal to the optical differential delay unit, to set the relative delay at two different bias values to select a layer of material inside the target area to measure an optical absorption of the selected layer at each and every wavelength from the different light sources.   
     
     
         10 . The device as in  claim 3 , wherein the optical imaging module further comprises:
 a plurality of tunable laser sources emitting light within different wavelength bands centered at different wavelengths as the probe light to the probe optic fiber, wherein the imaging optic fiber is configured to receive and guide the probe light at the different wavelength bands in a first propagation mode,   wherein the probe head is to reflect a first portion of the probe light back to the imaging optic fiber in the first propagation mode and direct a second portion of the light to the target area, and wherein the probe head collects reflection of the second portion from the target area and exports to the imaging optic fiber the reflection as a reflected second portion in a second propagation mode different from the first propagation mode;   a detection module to receive the reflected first portion and the reflected second portion in the waveguide and to extract information of the target area carried by the reflected second portion; and   a probe control unit to tune each tunable laser in a corresponding laser emitting wavelength band to obtain absorption measurements of the target area at different wavelengths within each corresponding wavelength band.   
     
     
         11 . The device as in  claim 1 , comprising:
 a liquid cooling unit coupled to the catheter to direct a cooling liquid that cools a surface of the target tissue, the liquid cooling unit including a balloon that receives the cooling liquid and is located in contact with the surface of the target tissue.   
     
     
         12 . A method for thermotherapy, comprising:
 directing an imaging optical beam to a target tissue to obtain image information;   processing the obtained image information of the target tissue to obtain a spatial distribution of the diseased locations of the target tissue;   generating a temperature map of the target tissue for thermotherapy based on the spatial distribution of the diseased locations of the target tissue; and   controlling the thermal energy delivery to each of the diseased locations and cooling at the surface of each diseased locations based on the temperature map to perform the thermotherapy.