In-vivo measurement of fluorescence bleaching of meso-tetra hydroxy phenyl chlorin (mTHPC) in the esophagus and the oral cavity

Martin Forrer; Thomas M. Glanzmann; Daniel Braichotte; Georges A. Wagnieres; Hubert van den Bergh; Jean-Francois Savary; Philippe Monnier

doi:10.1117/12.228901

27 December 1995 In-vivo measurement of fluorescence bleaching of meso-tetra hydroxy phenyl chlorin (mTHPC) in the esophagus and the oral cavity

Martin Forrer, Thomas M. Glanzmann, Daniel Braichotte, Georges A. Wagnieres, Hubert van den Bergh, Jean-Francois Savary, Philippe Monnier

Author Affiliations +

Proceedings Volume 2627, Optical Biopsies; (1995) https://doi.org/10.1117/12.228901
Event: BiOS Europe '95, 1995, Barcelona, Spain

Abstract

In vivo spectrofluorometric analysis during photodynamic therapy (PDT) is a tool to obtain information about fluorophore bleaching kinetics in tissue. Using a cylindrical esophageal light distributor for PDT with an integrated sensing fiber, together with a fluorescence detection setup, we can obtain tissue fluorescence spectra endoscopically in a clinical environment. This study was performed on patients with early squamous cell carcinomas in the esophagus. Patients were injected intravenously with 0.15 mg/kg of mTHPC and underwent PDT (lambda equals 514 nm, fluence rate equals 100 mW/cm²) 96 hours after injection. Bleaching kinetics of mTHPC and tissue autofluorescence at different wavelengths were recorded in real time and showed decreases in the observed fluorescence intensity in the 652 nm band of about 60% for light doses around 100 J/cm². Additional information on bleaching kinetics induced at another excitation wavelength, lambda equals 652 nm, was obtained by irradiations at much lower doses in the buccal cavity. The data are analyzed using a simplified mechanism in which singlet oxygen is the hypothetical reactive intermediate which can both bleach the mTHPC and the autofluorescent molecules. The differential equations are solved by applying the quasi stationary state approximation for the reactive intermediate. The experimental data at least do not appear to contradict this oversimplified mechanism.

Citation Download Citation

Martin Forrer, Thomas M. Glanzmann, Daniel Braichotte, Georges A. Wagnieres, Hubert van den Bergh, Jean-Francois Savary, and Philippe Monnier "In-vivo measurement of fluorescence bleaching of meso-tetra hydroxy phenyl chlorin (mTHPC) in the esophagus and the oral cavity", Proc. SPIE 2627, Optical Biopsies, (27 December 1995); https://doi.org/10.1117/12.228901

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available