title: Depth determination of chromophores in human skin by pulsed photothermal radiometry.
abstract: We report on the application of pulsed photothermal radiometry (PPTR) to determine the depth of in-vitro and in-vivo subsurface chromophores in biological materials. Measurements provided by PPTR in combination with a nonnegative constrained conjugate-gradient algorithm are used to determine the initial temperature distribution in a biological material immediately following pulsed laser irradiation. Within the experimental error, chromophore depths (50-450 µm) in 55 in-vitro collagen phantoms determined by PPTR and optical low-coherence reflectometry are equivalent. The depths of port-wine-stain blood vessels determined by PPTR correlate very well with their locations found by computer-assisted microscopic observation of histologic sections. The mean blood-vessel depth deduced from PPTR and histologic observation is statistically indistinguishable (p > 0.94).
authors.forename: T E
authors.initials: TE
authors.lastname: Milner
authors.forename: D J
authors.initials: DJ
authors.lastname: Smithies
authors.forename: D M
authors.initials: DM
authors.lastname: Goodman
authors.forename: A
authors.initials: A
authors.lastname: Lau
authors.forename: J S
authors.initials: JS
authors.lastname: Nelson