Journal of Environmental Pathology, Toxicology and Oncology

ISSN for PRINT: 0731-8898

For Online Access

Best Paper Award Selection - Editorial Board Site

2006, Volume25

Issue 1-2

546 pages

Issue price - $344.00

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, The Norwegian Radium Hospital, N-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, Oslo, Norway

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.

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