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Proceedings Paper

Integrating sphere effect in whole bladder wall photodynamic therapy at violet, green, and red wavelengths
Author(s): Hugo J. van Staveren; Johan F. Beek; Marleen Keijzer; Willem M. Star
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Paper Abstract

Fluence rates were measured in vivo at a piglet bladder wall during whole bladder wall (WBW) light irradiation at 458, 488, 514, 532, and 630 nm wavelengths. Bladder optical properties, the absorption-, scattering-, and anisotropy coefficient, were determined in vitro at these wavelengths using a double integrating sphere set-up. Monte Carlo (MC) computer simulations for WBW photodynamic therapy (PDT) were performed in a spherical geometry representing the bladder. The in vivo measured fluence multiplication factor ((beta) ) decreases from approximately equals 5 at 630 nm to approximately equals 1.5 at 458 nm. The simulated (beta) values, using the in vitro optical properties and non-absorbing (saline) bladder contents, are consistently larger with a minimum at 514/532 nm and a maximum at 458 and 630 nm. Simulations with slightly light absorbing bladder contents show that the inevitable urine in the cavity can at least partly be responsible for the lower in vivo values. Whereas the MC simulations use an in vitro absorption coefficient, the in vivo observed phenomenon might be attributed to additional light absorption by hemoglobin in the bladder tissue. Thus, WBW-PDT with red light is technically more advantageous than with green or blue light as this gives the strongest integrating sphere effect.

Paper Details

Date Published: 18 January 1995
PDF: 8 pages
Proc. SPIE 2323, Laser Interaction with Hard and Soft Tissue II, (18 January 1995); doi: 10.1117/12.199196
Show Author Affiliations
Hugo J. van Staveren, Dr. Daniel den Hoed Cancer Ctr. (Netherlands)
Johan F. Beek, Academic Medical Ctr. (Netherlands)
Marleen Keijzer, Delft Univ. of Technology (Netherlands)
Willem M. Star, Dr. Daniel den Hoed Cancer Ctr. (Netherlands)

Published in SPIE Proceedings Vol. 2323:
Laser Interaction with Hard and Soft Tissue II
Hans Joerg Albrecht; Guy P. Delacretaz; Thomas H. Meier; Rudolf W. Steiner; Lars Othar Svaasand; Martin J. C. van Gemert, Editor(s)

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