Method and apparatus for selective photothermolysis of veins

Abstract

A system and method are provided that are capable of selectively treating a vein using photothermolysis techniques, where an electromagnetic radiation is applied to tissue containing the vein. The radiation can be selected so that it may be more effectively absorbed by veins as compared to arteries. Thus, unwanted thermal damage to arteries in the vicinity of the vein being treated can be reduced or avoided. The radiation can have a frequency of approximately 654 nm, which can provide a ratio of absorption by veins to absorption by arteries of about 3.7. Other wavelengths near 654 nm may be provided, for example, which can have an absorption ratio greater than, e.g., about 3.3 to 3.6.

1 . A method for irradiating a vein of a region of interest (ROI) of a patient's body, the method comprising:
 selecting the vein of said ROI of the patient's body, said vein having a malformation; and   irradiating the vein with light having an operational wavelength, said vein having a vein absorption coefficient, at the operational wavelength, that is at least 3.3 times higher than the absorption coefficient of an artery of the patient's body at the same wavelength.   
     
     
         2 . A method according to  claim 1 , wherein the vein absorption coefficient is at least 3.6 times higher than the absorption coefficient of the artery of the patient's body at the operational wavelength. 
     
     
         3 . A method according to  claim 1 , wherein the vein absorption coefficient is at least 3.7 times higher than the absorption coefficient of the artery of the patient's body at the operational wavelength. 
     
     
         4 . A method according to  claim 1 , wherein said vein of the patient's body contains blood characterized by an absorption ratio, at the operational wavelength, of a first absorption coefficient of a deoxygenated hemoglobin to a second absorption coefficient of an oxygenated hemoglobin, said absorption ratio being greater than 9. 
     
     
         5 . A method according to  claim 1 , wherein said vein of the patient's body contains blood characterized by an absorption ratio, at the operational wavelength, of a first absorption coefficient of a deoxygenated hemoglobin to a second absorption coefficient of an oxygenated hemoglobin, said absorption ratio being greater than 10. 
     
     
         6 . A method according to  claim 1 , wherein said vein of the patient's body contains blood characterized by an absorption ratio, at the operational wavelength, of a first absorption coefficient of a deoxygenated hemoglobin to a second absorption coefficient of an oxygenated hemoglobin, said absorption ratio being greater than 10.2. 
     
     
         7 . A method according to  claim 1 , wherein the irradiating said vein of the patient's body with light includes irradiating said vein with light such as to eliminate perfusion in the malformation or reduce said vein. 
     
     
         8 . A method according to  claim 1 , wherein said malformation includes at least one of a varicose vein and a port wine stain, and wherein the irradiating the vascular element includes irradiating the vascular element such as to avoid scarring or necrosis of an artery of the ROI. 
     
     
         9 . A method according to  claim 1 , wherein the irradiating said vein with light includes irradiating said vascular element with light from at least one of a pulsed dye laser, a wavelength-shifted Nd:YAG laser, a frequency-doubled infrared laser, a high power diode laser array, and a fiber laser. 
     
     
         10 . A method according to  claim 1 , wherein the operational wavelength is between about 644 nm and about 642 nm. 
     
     
         11 . A method according to  claim 1 , further comprising cooling a surface of said ROI of the patient's body. 
     
     
         12 . A method for irradiating a vein of a region of interest (ROI) of a patient's body, the method comprising:
 selecting the vein of said ROI of the patient's body, said vein containing blood characterized by an absorption ratio of a first absorption coefficient of a deoxygenated hemoglobin to a second absorption coefficient of an oxygenated hemoglobin, said vein including a malformation; and   irradiating said vein with light having an operational wavelength at which said absorption ratio is greater than 9 and at which an absorption coefficient of the vein is at least 3.3 times higher than an absorption coefficient of an artery of the ROI at the same wavelength.   
     
     
         13 . A method according to  claim 12 , wherein the irradiating said vein with light includes irradiating said vein with light having an operational wavelength at which said absorption ratio is greater than 10. 
     
     
         14 . A method according to  claim 12 , wherein the irradiating said vein with light includes irradiating said vein with light having an operational wavelength at which said absorption ratio is greater than 10.2. 
     
     
         15 . A method according to  claim 12 , further comprising cooling a surface of said ROI of the patient's body. 
     
     
         16 . A method according to  claim 12 , wherein the irradiating said vein with light includes irradiating said vein with light such as to eliminate perfusion in the malformation or reduce said vein. 
     
     
         17 . A method according to  claim 12 , wherein said malformation includes at least one of a varicose vein and a port wine stain, and wherein the irradiating the vein includes irradiating the vein such as to avoid scarring or necrosis of an artery of the ROI. 
     
     
         18 . A method according to  claim 12 , wherein said operational wavelength is between about 632 nm and about 680 nm.