Low Profile Apparatus and Method for Phototherapy

Abstract

Disclosed herein are optical assemblies having thin, low profile shapes. These optical assemblies may be used with fiber coupled lasers and other light sources, including high power sources, to irradiate tissue at a wavelength suitable for inducing ablation or coagulation to a target depth, denaturation, thermal modification of a tissue, and/or preferential injury to a target tissue structure. Example optical assemblies can produce substantially uniform illumination patterns that are useful for treating superficial tissue, including the internal or luminal (e.g., esophageal) tissue. Some examples may have capability for cooling superficial tissue or skin, such as a detachable, reusable heat sink for active cooling without consumables, fluid pumps, or other cooling equipment.

1 . An apparatus for irradiating a tissue surface, comprising:
 a substantially rigid light guide plate configured to guide light from a lateral input surface in a propagation direction that is substantially parallel to a light-transmitting contact surface, the light-transmitting contact surface being configured to irradiate the tissue surface with light guided by the light guide plate.   
     
     
         2 . The apparatus of  claim 1  further wherein the light-transmitting contact surface is a surface of the light guide plate. 
     
     
         3 . The apparatus of  claim 1  further including:
 a contact element operably coupled to the light guide plate, and 
 wherein the light-transmitting contact surface is a surface of the contact element. 
 
     
     
         4 . The apparatus of  claim 1  further including:
 extraction features configured to direct light guided by the rigid light guide plate through the light-transmitting contact surface towards the tissue surface. 
 
     
     
         5 . The apparatus of  claim 4  wherein the extraction features are disposed in a pattern on the light guide plate. 
     
     
         6 . The apparatus of  claim 1  further including:
 a cooling layer configured to remove heat from the light transmitting contact surface via a cooling fluid. 
 
     
     
         7 . The apparatus of  claim 6  further including:
 at least one extraction feature configured to direct light guided by the rigid light guide plate through the light-transmitting contact surface towards the tissue surface, and 
 wherein the cooling fluid is in thermal contact with the at least one extraction feature. 
 
     
     
         8 . The apparatus of  claim 1  further including:
 a housing enclosing at least a portion of the light guide plate and having an opening at the lateral input surface of the light guide plate. 
 
     
     
         9 . The apparatus of  claim 8  further including:
 an air gap between a proximal surface of the light guide plate and an interior surface of the housing. 
 
     
     
         10 . The apparatus of  claim 9  further including:
 a cooling layer adjacent to a distal surface of the light guide plate, the cooling layer including a cooling fluid having an index of refraction that is lower than that of the light guide plate; 
 a contact element having a proximal surface adjacent to the cooling layer, and 
 wherein the light-transmitting contact surface is a distal surface of the contact element. 
 
     
     
         11 . The apparatus of  claim 10  further including:
 another air gap between the distal surface of the light guide plate and the cooling layer. 
 
     
     
         12 . The apparatus of  claim 8  further including:
 a cooling layer adjacent to a proximal surface of the light guide plate, the cooling layer including a cooling fluid having an index of refraction that is lower than that of the light guide plate. 
 
     
     
         13 . The apparatus of  claim 8  further including:
 extraction features disposed on the proximal surface of the light guide plate; 
 a reflecting plate configured to reflect light scattered by the extraction features towards the tissue surface; and 
 an extraction space between the reflecting plate and a proximal surface of the light guide plate. 
 
     
     
         14 . The apparatus of  claim 13  wherein the extraction space comprises a heat transfer fluid having a refractive index lower than that of the light guide plate. 
     
     
         15 . The apparatus of  claim 8  wherein the apparatus is configured to receive a detachable heat sink in thermal contact with the housing and the contact element. 
     
     
         16 . The apparatus of  claim 8  wherein the housing has a thickness of about 6 mm or less. 
     
     
         17 . The apparatus of  claim 1  wherein the light-contacting surface has a contact surface area of at least about 30 mm 2 . 
     
     
         18 . The apparatus of  claim 1  wherein the light-transmitting contact surface includes focusing features. 
     
     
         19 . The apparatus of  claim 1  wherein the contact element is configured to irradiate the tissue surface with light having a substantially uniform intensity distribution. 
     
     
         20 . The apparatus of  claim 1  further including:
 a light source operably coupled to the lateral input surface of the light guide plate and configured to provide the light guided by the light guide plate. 
 
     
     
         21 . A method of irradiating a tissue surface, comprising:
 guiding light in a propagation direction that is substantially parallel to the tissue surface via a substantially rigid light guide plate; and   irradiating the tissue surface with light guided by the light guide plate via a light-transmitting contact surface.   
     
     
         22 . The method of  claim 21  further including:
 coupling light from the light guide plate to the light-transmitting contact surface with at least one extraction feature on the light guide plate. 
 
     
     
         23 . The method of  claim 22  wherein the light guide plate includes a plurality of extraction features disposed in a pattern. 
     
     
         24 . The method of  claim 22  further including:
 cooling the at least one extraction feature. 
 
     
     
         25 . The method of  claim 21  wherein irradiating the tissue surface includes irradiating the tissue surface with light having a substantially uniform intensity distribution. 
     
     
         26 . The method of  claim 21  further including:
 generating the light with a light source operably coupled to the lateral input surface of the light guide plate. 
 
     
     
         27 . The method of  claim 21  further including:
 removing heat from the light-transmitting contact surface via a cooling fluid. 
 
     
     
         28 . The method of  claim 27  wherein the cooling fluid has an index of refraction higher than that of the light guide plate (only when cooling fluid is next to light guide plate) 
     
     
         29 . The method of  claim 21  further including:
 removing heat from the contact element with a detachable heat sink. 
 
     
     
         30 . The method of  claim 21  wherein the light-contacting surface has a contact surface area of at least about 30 mm 2 . 
     
     
         31 . The method of  claim 21  wherein the light-transmitting contact surface includes focusing features. 
     
     
         32 . The method of  claim 21  wherein at least a portion of the light guide plate is enclosed in a housing. 
     
     
         33 . The method of  claim 32  wherein the housing has a thickness of about 6 mm or less. 
     
     
         34 . An apparatus for irradiating a tissue surface, comprising:
 a plurality of reflecting elements configured to direct light onto respective segment areas of a window element, the window element having a light-transmitting contact surface configured to irradiate the tissue surface.   
     
     
         35 . The apparatus of  claim 34  further including:
 a cooling layer configured to remove heat from the plurality of reflecting elements via a cooling fluid. 
 
     
     
         36 . The apparatus of  claim 34  wherein the plurality of reflecting elements includes at least one partially reflecting prism or mirror disposed in the path of an optical beam. 
     
     
         37 . A method of irradiating a tissue surface, comprising:
 directing light onto a window element with a plurality of reflecting elements, each of which reflects light onto a respective segment area of the window element; and   irradiating the tissue surface with the reflected light via a light-transmitting contact surface of the window element.   
     
     
         38 . The method of  claim 37  further including:
 removing heat from the plurality of reflecting elements via a cooling fluid. 
 
     
     
         39 . The method of  claim 38  wherein removing heat includes placing the cooling fluid in contact with optical surfaces of the plurality of reflecting elements. 
     
     
         40 . The method of  claim 37  wherein directing light onto at least one of the respective segment areas of the window element including reflecting light off a partially reflecting prism or mirror. 
     
     
         41 . An apparatus for irradiating an interior surface of a lumen, the apparatus comprising:
 a catheter;   at least one optical fiber disposed along a length of the catheter; and   a plurality of optical assemblies disposed at the distal end of the catheter, at least one of the optical assemblies being configured to direct light guided by the at least one optical fiber to the interior surface of the lumen via a light-transmitting contact surface.   
     
     
         42 . The apparatus of  claim 41  further including:
 an expandable element configured to place the light-transmitting contact surface in contact with the interior surface of the lumen upon expansion of the expandable element within the lumen. 
 
     
     
         43 . The apparatus of  claim 41  wherein the light-transmitting contact surface is curved to conform to the interior surface of the lumen. 
     
     
         44 . The apparatus of  claim 41  in combination with a disposable sleeve covering the plurality of optical assemblies. 
     
     
         45 . The apparatus of  claim 41  further including:
 a scanner optically coupled to each of the plurality of optical assemblies and configured to distribute light sequentially to each of the plurality of optical assemblies. 
 
     
     
         46 . A method of irradiating an interior surface of a lumen, the method comprising:
 at each of a plurality of optical assemblies disposed at a distal end of a catheter, guiding light in a propagation direction that is substantially parallel to a respective light-transmitting contact surface; and   at each of the plurality of optical assemblies, irradiating the interior surface of the lumen with light guided by light guide plate via the respective light-transmitting contact surface.   
     
     
         47 . The method of  claim 46  further including:
 inserting the plurality of optical assemblies into the lumen; and 
 placing the light-transmitting contact surfaces in contact with the interior surface of the lumen. 
 
     
     
         48 . The method of  claim 46  further including:
 covering the plurality of optical assemblies with a disposable covering; and 
 inserting the plurality of optical assemblies into the lumen. 
 
     
     
         49 . The method of  claim 46  further including:
 distributing light sequentially to each of the plurality of optical assemblies.