System for causing ablation of irradiated material of living tissue while not causing damage below a predetermined depth

Abstract

A system for causing uniform ablation of irradiated material of living tissue while not causing damage below a predetermined depth where laser radiation is provided sequentially and continuously in a predetermined pattern is disclosed.

What is claimed: 
     
       1. A system for causing ablation of an irradiated material of living tissue while not causing necrosis below a predetermined depth .Iadd.beneath a level of the ablation.Iaddend., said irradiated material consisting of a plurality of elements; said system including: means for generating a beam of laser radiation to be uniformly absorbed by said irradiated material;   a scanner means for moving said beam of laser radiation in a predetermined pattern on said irradiated material so that said elements of said irradiated material are sequentially and continuously irradiated; and   means for controlling the scanner means to move said beam of laser radiation in said predetermined pattern so that ablation of said irradiated material of living tissue is caused uniformly but .[.only to a.]. .Iadd.necrosis is not caused below the .Iaddend.predetermined depth .Iadd.beneath the level of the ablation.Iaddend..   
     
     
       2. The system according to claim 1, wherein each of said elements of said irradiated material experiences a predetermined minimum time interval between applications of radiation thereto. 
     
     
       3. The system as defined in claim 2 in which said predetermined minimum time interval is 0.1 of a second. 
     
     
       4. The system as defined in claim 3 wherein the laser beam has an average power density of at least 40 watts/mm 2 . 
     
     
       5. The system according to any one of claims 1-4, wherein the scanner causes the beam of laser radiation to trace Lissajous figures over said irradiated material. 
     
     
       6. The system according to any one of claims 1-4 in which said means for generating a beam of laser radiation is a carbon dioxide laser. 
     
     
       7. The system as defined in claim 5 in which said means for generating a beam of laser radiation is a carbon dioxide laser. .Iadd. 
     
     
       8.  The system as defined in claim 1, wherein the means for controlling the scanner means moves the beam of laser radiation to scan the predetermined pattern so that each of said elements of irradiated material experiences exposure to laser radiation for less than 1 millisecond per scan..Iaddend..Iadd.9. The system as defined in claim 8, wherein the means for controlling the scanner means moves the beam of laser radiation to expose each of the elements of the irradiated material sequentially to an application of the laser radiation during each one of successive scans of the predetermined pattern and so that each of the elements of the irradiated material experience a predetermined minimum time interval before being exposed to the application of the laser radiation thereto during the next one of the successive scans..Iaddend..Iadd.10. The system as defined in claim 9, wherein the predetermined minimum time interval is 0.1 of a second..Iaddend.