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 . An apparatus for irradiating a portion of a patient's scalp or skull with light, the apparatus comprising:
 a source of light; and   an output optical element in optical communication with the source, wherein the output optical element comprises an emission surface configured to emit a pulsed light beam comprising a plurality of pulses having a temporal pulsewidth in a range between 0.1 millisecond and 150 seconds, the pulsed light beam having a cross-sectional area greater than about 2 cm 2  at the emission surface of the output optical element, having a time-averaged irradiance in a range of about 10 mW/cm 2  to about 10 W/cm 2  across the cross-sectional area.   
     
     
         2 . The apparatus of  claim 1 , wherein the pulsed light beam stimulates, excites, induces, or otherwise supports one or more intercellular or intracellular biological processes involved in the survival, regeneration, or restoration of performance or viability of brain cells. 
     
     
         3 . The apparatus of  claim 1 , wherein pulsed light beam has a duty cycle, wherein the temporal pulsewidth and the duty cycle are sufficient for the pulsed light beam to penetrate the skull to modulate membrane potentials, thereby enhancing cell survival, cell function, or both of the irradiated brain cells. 
     
     
         4 . The apparatus of  claim 1 , wherein the pulsed light beam at the emission surface has a beam diameter in a range between 10 millimeters and 40 millimeters, an average irradiance per pulse in a range between 10 mW/cm 2  and 10 W/cm 2 , one or more wavelengths in a range between 600 nanometers and 980 nanometers, and a duty cycle in a range between 10% and 30%. 
     
     
         5 . A method of irradiating a surface with light, the method comprising:
 irradiating the surface with at least one pulsed light beam emitted from an emission surface of an optical element, the at least one pulsed light beam comprising 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 having 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 .   
     
     
         6 . The method of  claim 5 , wherein the beam cross-sectional area at the emission surface is in a range between about 1 cm 2  and about 20 cm 2 . 
     
     
         7 . The method of  claim 5 , wherein the average irradiance per pulse at the emission surface is in a range between about 10 mW/cm 2  and about 10 W/cm 2 . 
     
     
         8 . The method of  claim 5 , wherein the average irradiance per pulse at the emission surface is in a range between about 100 mW/cm 2  and about 1 W/cm 2 . 
     
     
         9 . The method of  claim 5 , wherein the temporal pulsewidth is in a range between about 0.1 millisecond and about 100 milliseconds. 
     
     
         10 . The method of  claim 5 , wherein the at least one pulsed light beam has one or more wavelengths are in a range between about 600 nanometers and about 980 nanometers. 
     
     
         11 . The method of  claim 5 , wherein the at least one pulsed light beam has a duty cycle in a range between about 1% and about 80%. 
     
     
         12 . The method of  claim 5 , wherein the at least one pulsed light beam has a beam divergence angle at the emission surface greater than zero and less than 35 degrees. 
     
     
         13 . The method of  claim 5 , wherein the irradiated surface comprises at least a portion of the scalp or skull of a patient whose brain has experienced at least one physical trauma, at least a portion of the at least one pulsed light beam transmitted through the skull to irradiate at least a portion of the patient's brain. 
     
     
         14 . The method of  claim 13 , wherein the irradiated surface comprises an irradiated portion of the scalp, and the irradiated portion of the scalp is not blanched while irradiating the portion of the scalp. 
     
     
         15 . The method of  claim 13 , wherein the irradiated surface comprises an irradiated portion of the scalp, and the irradiated portion of the scalp is blanched while irradiating the portion of the scalp. 
     
     
         16 . The method of  claim 13 , wherein the irradiated surface is cooled while irradiating the irradiated surface. 
     
     
         17 . The method of  claim 13 , wherein the irradiated surface is not cooled while irradiating the irradiated surface. 
     
     
         18 . The method of  claim 13 , wherein the irradiated surface comprises an irradiated portion of the scalp, and the method further comprises removing at least a portion of the hair from the irradiated portion of the scalp prior to irradiating the irradiated portion of the scalp. 
     
     
         19 . The method of  claim 13 , wherein irradiating the surface comprises sequentially irradiating a plurality of treatment sites of the scalp with the pulsed light beam. 
     
     
         20 . The method of  claim 19 , wherein the plurality of treatment sites comprises at least 10 treatment sites. 
     
     
         21 . The method of  claim 19 , wherein the plurality of treatment sites comprises between 15 and 25 treatment sites. 
     
     
         22 . The method of  claim 13 , wherein the average irradiance at the scalp or skull is selected to provide an average irradiance greater than 0.01 mW/cm 2  at a depth of approximately 2 centimeters below the dura. 
     
     
         23 . The method of  claim 13 , wherein the light is transmitted through a region of the patient's skull containing an excess amount of hemorrhagic blood due to the at least one physical trauma. 
     
     
         24 . The method of  claim 5 , wherein the irradiated surface comprises a portion of a light-detection system configured to measure one or more parameters of the pulsed light beam. 
     
     
         25 . The method of  claim 24 , further comprising measuring the one or more parameters of the pulsed light beam impinging the irradiated surface. 
     
     
         26 . A method of treating a patient's brain, the method comprising:
 irradiating at least a portion of the scalp or skull of the patient with at least one pulsed light beam comprising a plurality of pulses transmitted through the patient's skull to irradiate at least a portion of the brain, the at least one pulsed light beam having a temporal profile comprising a time-averaged irradiance at the scalp averaged over one second in a range between about 100 mW/cm 2  and about 10 W/cm 2  and a peak irradiance at the scalp in a range between about 12.5 mW/cm 2  and about 1000 W/cm 2 .   
     
     
         27 . The method of  claim 26 , wherein the temporal profile does not optimize the thermal relaxation of the irradiated tissue. 
     
     
         28 . The method of  claim 26 , wherein the at least one pulsed light beam has a beam cross-sectional area at the scalp greater than about 2 cm 2 , and one or more wavelengths in a range between about 780 nanometers and about 840 nanometers. 
     
     
         29 . The method of  claim 26 , wherein the temporal profile further comprises a temporal pulsewidth in a range between about 0.1 millisecond and about 300 milliseconds and a duty cycle in a range between about 10% and about 30%. 
     
     
         30 . The method of  claim 26 , wherein irradiating at least a portion of the scalp or skull comprises sequentially irradiating a plurality of treatment sites with a plurality of pulsed light beams. 
     
     
         31 . The method of  claim 26 , wherein irradiating the at least a portion of the scalp or skull is performed for a time period of 60 seconds to 600 seconds. 
     
     
         32 . A method of treating a patient who has experienced a traumatic brain injury, the method comprising noninvasively irradiating at least a portion of the patient's scalp or skull with pulsed light penetrating the patient's skull to irradiate and stimulate brain cells of the patient, the pulsed light having a temporal profile comprising an average irradiance per pulse, a temporal pulse width, and a pulse duty cycle, the temporal profile selected to modulate membrane potentials in order to enhance, restore, or promote cell survival, cell function, or both of the irradiated brain cells following the traumatic brain injury. 
     
     
         33 . The method of  claim 32 , wherein the average irradiance per pulse is in a range between about 10 mW/cm 2  and about 10 W/cm 2 . 
     
     
         34 . The method of  claim 32 , wherein the pulsed light comprises a light beam having a beam cross-sectional area in a range between 2 cm 2  and 20 cm 2 . 
     
     
         35 . The method of  claim 32 , wherein the temporal pulse width is in a range between about 0.1 millisecond and about 300 milliseconds. 
     
     
         36 . The method of  claim 32 , wherein the pulse duty cycle is in a range between about 10% and about 30%. 
     
     
         37 . A method of treating a patient experiencing a neurodegenerative disease or depression, the method comprising noninvasively irradiating at least a portion of the patient's scalp or skull with pulsed light penetrating the patient's skull to irradiate and stimulate brain cells of the patient, the pulsed light having a temporal profile comprising an average irradiance per pulse, a temporal pulse width, and a pulse duty cycle, the temporal profile selected to modulate membrane potentials in order to enhance, restore, or promote cell survival, cell function, or both of the irradiated brain cells. 
     
     
         38 . The method of  claim 37 , wherein the neurodegenerative disease comprises Alzheimer's Disease or Parkinson's Disease.