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System for integrated interstitial photodynamic therapy and dosimetric monitoring

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Author

Summary, in English

Photodynamic therapy for the treatment of cancer relies on the presence of light, sensitizer and oxygen. By monitoring these three parameters during the treatment a better understanding and treatment control could possibly be achieved. Here we present data from in vivo treatments of solid skin tumors using an instrument for interstitial photodynamic therapy with integrated dosimetric monitoring. By using intra-tumoral ALA-administration and interstitial light delivery solid tumors are targeted. The same fibers are used for measuring the fluence rate at the treatment wavelength, the sensitizer fluorescence and the local blood oxygen saturation during the treatment. The data presented is based on 10 treatments in 8 patients with thick basal cell carcinomas. The fluence rate measurements at 635 nm indicate a major treatment induced absorption increase, leading to a limited light penetration at the treatment wavelength. This leads to a far from optimal treatment since the absorption increase prevents peripheral tumor regions from being fully treated. An interactive treatment has been implemented assisting the physician in delivering the correct light dose. The absorption increase can be compensated for by either prolonging the treatment time or increasing the output power of each individual treatment fiber. The other parameters of importance, i.e. the sensitizer fluorescence at 705 nm and the local blood oxygen saturation, are monitored in order to get an estimate of the amount of photobleaching and oxygen consumption. Based on the oxygen saturation signal, a fractionized irradiation can be introduced in order to allow for a re-oxygenation of the tissue

Publishing year

2005

Language

English

Pages

130-140

Publication/Series

Proceedings of the SPIE - The International Society for Optical Engineering

Volume

5689

Issue

1

Document type

Conference paper

Publisher

SPIE

Topic

  • Dermatology and Venereal Diseases

Keywords

  • peripheral tumor region
  • photodynamic therapy
  • dosimetric monitoring
  • integrated interstitial system
  • 635 nm
  • cancer
  • solid skin tumors
  • sensitizer fluorescence
  • intra-tumoral ALA-administration
  • local blood oxygen saturation
  • basal cell carcinomas
  • fractionized irradiation
  • oxygen saturation signal
  • photobleaching
  • 705 nm

Conference name

Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XIV

Conference date

2005-01-22

Conference place

San Jose, CA, United States

Status

Published

ISBN/ISSN/Other

  • ISSN: 1996-756X
  • ISSN: 0277-786X