Method and Apparatus for Irradiating a Surface with Pulsed Light

Abstract

A method and apparatus irradiates a surface with at least one pulsed light beam emitted from an emission surface of an optical element. The at least one pulsed light beam comprises a plurality of pulses having a temporal pulsewidth in a range between about 0.1 millisecond and about 150 seconds. The at least one pulsed light beam has a beam cross-sectional area at the emission surface greater than about 2 cm 2 and a time-averaged irradiance in a range between about 1 mW/cm 2 and about 100 W/cm 2 .

1 .- 38 . (canceled) 
     
     
         39 . A method of irradiating a portion of a scalp or skull of a patient with light, the method comprising:
 delivering a pulsed light beam to the scalp or skull of the patient from an emission surface of   
       an output optical element in communication with a source of light;
 providing a thermal conduit in thermal communication with the output optical element and with a cooling mechanism; and 
 cooling the output optical element using the cooling mechanism via the thermal conduit, 
 wherein the pulsed light beam comprises a plurality of pulses having a temporal pulsewidth in a range between 0.1 millisecond and 150 seconds, and having a temporal profile comprising a time-averaged irradiance in a range of 10 mW/cm 2  to 10 W/cm 2  across a cross-sectional area, and 
 wherein the temporal profile does not optimize a thermal relaxation of an irradiated brain tissue. 
 
     
     
         40 . The method of  claim 39 , further comprising selecting the patient, wherein the patient is selected at least partly because the patient has experienced one or more conditions selected from the group consisting of a primary destructive event, Parkinson's disease, and depression. 
     
     
         41 . The method of  claim 39 , wherein the pulsed light beam has a fluence at a cortical surface of a brain of the patient between 12.5 μJ/cm 2  to 1 J/cm 2 . 
     
     
         42 . The method of  claim 39 , wherein the pulsed light beam at the emission surface has a beam diameter in a range between 10 millimeters and 40 millimeters and an average irradiance per pulse in a range between 10 mW/cm 2  and 10 W/cm 2 . 
     
     
         43 . The method of  claim 39 , wherein the source of light comprises a laser light source. 
     
     
         44 . The method of  claim 39 , wherein the output optical element comprises sapphire. 
     
     
         45 . The method of  claim 39 , wherein the output optical element comprises diamond, calcium fluoride, or zinc selenide. 
     
     
         46 . The method of  claim 39 , wherein the output optical element comprises a rigid, optically transmissive, and thermally conductive material. 
     
     
         47 . The method of  claim 39 , wherein the output optical element comprises a flexible optically transmissive, and thermally conductive material. 
     
     
         48 . The method of  claim 39 , wherein the output optical element has a thermal conductivity of at least 10 watts/meter-K. 
     
     
         49 . The method of  claim 39 , wherein the emission surface is concave to conform to a curvature of the scalp or skull of the patient, thereby reducing or preventing air gaps from forming between the emission surface and the scalp or skull of the patient. 
     
     
         50 . The method of  claim 39 , wherein the emission surface comprises one or more optical coatings, films, layers, or membranes configured to reduce back reflections. 
     
     
         51 . The method of  claim 39 , wherein the emission surface comprises one or more diffusers. 
     
     
         52 . The method of  claim 39 , wherein the temporal pulsewidth is in a range between 0.1 millisecond and 300 milliseconds. 
     
     
         53 . The method of  claim 39 , wherein the output optical element has an aperture diameter of less than 33 millimeters. 
     
     
         54 . The method of  claim 39 , wherein the pulsed light beam comprises one or more wavelengths in a range between 600 nanometers and 1064 nanometers. 
     
     
         55 . The method of  claim 39 , wherein the time-averaged irradiance at the scalp or skull provides a time-averaged irradiance greater than 0.01 mW/cm 2  to a target subsurface tissue of a brain of the patient below a dura of the patient. 
     
     
         56 . The method of  claim 39 , wherein the time-averaged irradiance at the emission surface averaged over one second is in a range between 100 mW/cm 2  and 10 W/cm 2  and a peak irradiance at the scalp is in a range between 10 mW/cm 2  and 10 W/cm 2 . 
     
     
         57 . The method of  claim 39 , wherein the pulsed light beam has a duty cycle in a range between 10% and 30%. 
     
     
         58 . The method of  claim 39 , wherein a timing of the temporal profile corresponds to a timing of a biomolecular process involved in an absorption of one or more photons in the irradiated brain tissue. 
     
     
         59 . The method of  claim 39 , wherein the pulsed light beam has a cross-sectional area greater than 2 cm 2  at the emission surface of the output optical element.