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环境病理学,毒理学和肿瘤学期刊
影响因子: 1.241 5年影响因子: 1.349 SJR: 0.356 SNIP: 0.613 CiteScore™: 1.61

ISSN 打印: 0731-8898
ISSN 在线: 2162-6537

环境病理学,毒理学和肿瘤学期刊

DOI: 10.1615/JEnvironPatholToxicolOncol.v25.i1-2.200
pages 307-320

Spectroscopic Measurements of Photoinduced Processes in Human Skin after Topical Application of the Hexyl Ester of 5-Aminolevulinic Acid

Lu Zhao
Department of Physics and Technology, University of Bergen, Allégt. 55, N-5007 Bergen, Norway
Kristian Pagh Nielsen
Department of Physics and Technology, University of Bergen, Bergen, Norway
Asta Juzeniene
Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0310 Oslo, Norway
Petras Juzenas
The Norwegian Cancer Society; Department of Radiation Biology, The Norwegian Radium Hospital, Oslo, N-0310 Oslo, Norway
Vladimir Lani
Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, NO-0310 Montebello, Oslo, Norway
Li-Wei Ma
Department of Radiation Biophysics, Institute for Cancer Research, Rikshospital-Radiumhospital HF and Plasma/Room Physics, University of Oslo, Oslo, Norway
Knut Stamnes
Light and Life Laboratory, Stevens Institute of Technology, Hoboken, NJ 07030
Jakob J. Stamnes
Department of Physics and Technology, University of Bergen, Allégt. 55, N-5007 Bergen, Norway
Johan Moan
Department of Radiation Biophysics, Institute for Cancer Research, Rikshospital-Radiumhospital HF and Plasma/Room Physics, University of Oslo; lnstitute of Physics, University of Oslo, Blindern, Oslo, Norway

ABSTRACT

Although 5-aminolevulinic acid, ALA, and its derivatives, have been widely studied and applied in clinical photodynamic therapy (PDT), there is still a lack of reliable and non-invasive methods and technologies to evaluate physiological parameters of relevance for the therapy, such as erythema, melanogenesis, and oxygen level. We have investigated the kinetics of these parameters in human skin in vivo during and after PDT with the hexyl ester of ALA, ALA-Hex. Furthermore, the depth of photosensitizer (protoporphyrin IX, PpIX) production after different application times was investigated. It was found that the depth increased with increasing application time of ALA-Hex. We also investigated the depth of PpIX before and after light exposure causing 50% photobleaching at 407 nm. The PpIX localized in superficial layers of the normal tissue was removed during the bleaching. Thus, after bleaching, the remaining PpIX was localized mainly in the deeper layers of normal tissue. We have applied fluorescence emission spectroscopy, fluorescence excitation spectroscopy, and reflectance spectroscopy in the study of the above-mentioned parameters. In conclusion, fluorescence excitation spectroscopy and reflectance spectroscopy are simple, useful, reliable, and noninvasive techniques in the evaluation of the processes taking place in human skin in vivo during and after PDT. Using these methods we were able to quantify melanogenesis, O2 level, erythema, vasoconstriction, and vasodilatation.