title: Trends in nanosecond melanosome microcavitation up to 1540 nm.
abstract: Thresholds for microcavitation of bovine and porcine melanosomes were previously reported, using single nanosecond (ns) laser pulses in the visible (532 nm) and the near-infrared (NIR) from 1000 to 1319 nm. Here, we report average radiant exposure thresholds for bovine melanosome microcavitation at additional NIR wavelengths up to 1540 nm, which range from ∼0.159 J∕cm2 at 800 nm to 4.5 J∕cm2 at 1540 nm. Melanosome absorption coefficients were also estimated, and decreased with increasing wavelength. These values were compared to retinal pigment epithelium coefficients, and to water absorption, over the same wavelength range. Corneal total intraocular energy retinal damage threshold values were estimated and compared to the previous (2007) and recently changed (2014) maximum permissible exposure (MPE) safe levels. Results provide additional data that support the recent changes to the MPE levels, as well as the first microcavitation data at 1540 nm, a wavelength for which melanosome microcavitation may be an ns-pulse skin damage mechanism.
authors.affiliation: Human Effectiveness Directorate, Bioeffects Division, Optical Radiation Branch, 711th Human Performance Wing, Fort Sam Houston, Texas 78234, United States.
authors.forename: Morgan S
authors.initials: MS
authors.lastname: Schmidt
authors.affiliation: Human Effectiveness Directorate, Bioeffects Division, Optical Radiation Branch, 711th Human Performance Wing, Fort Sam Houston, Texas 78234, United States.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Kennedy
authors.affiliation: Engility Corporation, Fort Sam Houston, Texas 78234, United States.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Noojin
authors.affiliation: Engility Corporation, Fort Sam Houston, Texas 78234, United States.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Vincelette
authors.affiliation: Human Effectiveness Directorate, Bioeffects Division, Optical Radiation Branch, 711th Human Performance Wing, Fort Sam Houston, Texas 78234, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Thomas
authors.affiliation: Human Effectiveness Directorate, Bioeffects Division, Optical Radiation Branch, 711th Human Performance Wing, Fort Sam Houston, Texas 78234, United States.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Rockwell
mesh_terms: D065638:Absorption, Radiation / Q000502:physiology; D000818:Animals; D002417:Cattle; D002458:Cell Fractionation / Q000379:methods; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D007834:Lasers; D008452:Maximum Allowable Concentration; D020460:Melanosomes / Q000502:physiology* / Q000528:radiation effects* / Q000648:ultrastructure; D011829:Radiation Dosage; D055213:Retinal Pigment Epithelium / Q000502:physiology* / Q000528:radiation effects* / Q000648:ultrastructure; D013045:Species Specificity; D013552:Swine