Tissue optics and dosimetry for photodynamic cancer therapy in the esophagus

For safe light dosimetry in photodynamic therapy (PDT) in organs like the oesophagus, the knowledge of the space irradiance distribution in tissue is especially important. In order to obtain this distribution we are studying two methods which are being evaluated in a clinical environment. The first method is non invasive and is based on the measurement of optical tissue parameters. For this measurement, several types of optical probe have been developed. The second method is invasive and measures light in situ by means of an optical fiber probe with a fluorescent tip. Together with these measuring techniques and results we present some simple notions of light dosimetry which can be used to improve the safety and the efficacy of the clinical PDT.

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