title: Noninvasive fluorescence excitation spectroscopy during application of 5-aminolevulinic acid in vivo.
abstract: The fluorescence of PpIX induced by topical application of 5-aminolevulinic acid (ALA) in normal mouse skin was studied noninvasively by means of a fibre optic probe. The fluorescence excitation spectrum of PpIX exhibits five distinct peaks at around 408. 510, 543, 583 and 633 nm under fluorescence monitoring at the second emission peak of PpIX (705 nm). The transmission of the excitation light is wavelength dependent: the long wavelength light (>600 nm) penetrates deeper into the tissues by a factor of 6 compared with the short wavelength light (<590 nm). Thus, the fluorescence excitation spectrum of PpIX measured on the surface of the skin can be used to estimate the depth of the penetration of topically applied ALA. The fluorescence excitation spectra calculated for the depth 1.1 mm obtained the best fit with the experimentally measured spectra after topical application of ALA.
authors.affiliation: Department of Biophysics,The Norwegian Radium Hospital, Oslo, Norway.
authors.forename: Petras
authors.initials: P
authors.lastname: Juzenas
authors.forename: Asta
authors.initials: A
authors.lastname: Juzeniene
authors.forename: Olav
authors.initials: O
authors.lastname: Kaalhus
authors.forename: Vladimir
authors.initials: V
authors.lastname: Iani
authors.forename: Johan
authors.initials: J
authors.lastname: Moan
mesh_terms: D000622:Aminolevulinic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D000818:Animals; D005260:Female; D006801:Humans; D008027:Light; D008954:Models, Biological; D008956:Models, Chemical; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D011524:Protoporphyrins / Q000737:chemistry; D051381:Rats; D011923:Rats, Nude; D012867:Skin; D013050:Spectrometry, Fluorescence; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
chemical_list: D017319:Photosensitizing Agents; D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX