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Journal of Biomedical Optics

In vivo fluence rate measurements during Foscan®-mediated photodynamic therapy of persistent and recurrent nasopharyngeal carcinomas using a dedicated light applicator
Author(s): R. L. P. van Veen; H. Nyst; S. R. Indrasari; M. A. Yudharto; D. J. Robinson; I. B. Tan; C. Meewis; R. Peters; Stefan B. Spaniol; Fiona A. Stewart; P.C. Levendag; Henricus J. C. M. Sterenborg
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Paper Abstract

The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan®-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy–induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan® absorption.

Paper Details

Date Published: 1 July 2006
PDF: 7 pages
J. Biomed. Opt. 11(4) 041107 doi: 10.1117/1.2338009
Published in: Journal of Biomedical Optics Volume 11, Issue 4
Show Author Affiliations
R. L. P. van Veen, Univ. Medisch Ctr. Rotterdam (Netherlands)
H. Nyst, Het Nederlands Kanker Instituut - Antoni van Leeuwenhoek Ziekenhuis (Netherlands)
S. R. Indrasari, Dr. Sarjito Hospital (Indonesia)
M. A. Yudharto, Dr. Cipto Mangunkusumo Hospital (Indonesia)
D. J. Robinson, Erasmus Univ. Medical Ctr. (Netherlands)
I. B. Tan, Het Nederlands Kanker Instituut - Antoni van Leeuwenhoek Ziekenhuis (Netherlands)
C. Meewis, Erasmus Univ. Medical Ctr. (Netherlands)
R. Peters, Erasmus Univ. Medical Ctr. (Netherlands)
Stefan B. Spaniol, CeramOptec GmbH (Germany)
Fiona A. Stewart, Netherlands Cancer Institute (Netherlands)
P.C. Levendag, Univ. Medisch Ctr. Rotterdam (Netherlands)
Henricus J. C. M. Sterenborg, Erasmus Univ. Medical Ctr. (Netherlands)


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