Photophysics and photochemistry of photodynamic therapy: fundamental aspects
Top Cited Papers
- 5 February 2008
- journal article
- review article
- Published by Springer Science and Business Media LLC in Lasers in Medical Science
- Vol. 24 (2), 259-268
- https://doi.org/10.1007/s10103-008-0539-1
Abstract
Photodynamic therapy (PDT) is a treatment modality for cancer and various other diseases. The clinical protocol covers the illumination of target cells (or tissue), which have been loaded with a photoactive drug (photosensitizer). In this review we describe the photophysical and primary photochemical processes that occur during PDT. Interaction of light with tissue results in attenuation of the incident light energy due to reflectance, absorption, scattering, and refraction. Refraction and reflection are reduced by perpendicular light application, whereas absorption can be minimized by the choice of a photosensitizer that absorbs in the far red region of the electromagnetic spectrum. Interaction of light and the photosensitizer can result in degradation, modification or relocalization of the drug, which differently affect the effectiveness of PDT. Photodynamic therapy itself, however, employs the light-induced chemical reactions of the activated photosensitizer (triplet state), resulting in the production of various reactive oxygen species, amongst them singlet oxygen as the primary photochemical product. Based on these considerations, the properties of an ideal photosensitizer for PDT are discussed. According to the clinical experience with PDT, it is proposed that the innovative concept of PDT is most successfully implemented into the mainstream of anticancer therapies by following an application-, i.e. tumor-centered approach with a focus on the actual clinical requirements of the respective tumor type.Keywords
This publication has 67 references indexed in Scilit:
- Photodynamic therapy: a new antimicrobial approach to infectious disease?Photochemical & Photobiological Sciences, 2004
- Photodynamic therapy for cancerNature Reviews Cancer, 2003
- A spectroscopic study of the photobleaching of protoporphyrin IX in solutionLasers in Medical Science, 2003
- Photodynamic therapy: a new concept in medical treatmentBrazilian Journal of Medical and Biological Research, 2000
- Photodynamic TherapyDrugs & Aging, 1999
- Dynamic fluorescence changes during photodynamic therapy in vivo and in vitro of hydrophilic A1 (III) phthalocyanine tetrasulphonate and lipophilic ZN(II) phthalocyanine administered in liposomesJournal of Photochemistry and Photobiology B: Biology, 1996
- QUANTITATIVE OPTICAL SPECTROSCOPY FOR TISSUE DIAGNOSISAnnual Review of Physical Chemistry, 1996
- DEFINITION OF TYPE I and TYPE II PHOTOSENSITIZED OXIDATIONPhotochemistry and Photobiology, 1991
- Effect of bleaching of porphyrin sensitizers during photodynamic therapyCancer Letters, 1986
- IN VIVO and POST MORTEM MEASUREMENTS OF THE ATTENUATION SPECTRA OF LIGHT IN MAMMALIAN TISSUESPhotochemistry and Photobiology, 1985