In vivo determination of tumor optical parameters in esophageal carcinoma

Abstract

The knowledge of tumor optical properties seems to be necessary to adapt dosimetry to the individual situation and manage optimal results of PDT in esophageal cancer.

In-vivo measurements of penetration depth, oxygenation, and drug concentration using broadband absorption spectroscopy in human tissues before and after photodynamic therapy

“…Tumors tend to have lower penetration depth (3-4 mm) than small and large bowel but higher value than liver. These values are in reasonable agreement with the values of other published in vivo data in human normal brain, prostatic carcinoma, and esophageal carcinoma [6][7][8][9] . In our results, peritoneum shows lower penetration depth than expected value (higher than small and large bowel) based on their histological structures.…”

Comparison of 5‐aminolaevulinic acid and porphyrin photosensitization for photodynamic therapy of malignant bronchial stenosis: A clinical pilot study

“…During treatment, the radial light diffusing cylinder and/or balloon applicator systeme was closely applied to the surface of the tumor. The light dose was calculated as 100 j/cm 2 of tumor length [13]. Light at 630 nm was applied by an KTP-Nd:YAG laser having a DYE module (Laserscope 1 Surgical Systems, Gwent, UK).…”

Photodynamic therapy for esophageal carcinoma*

“…The optical parameters of esophageal carcinomas vary with different tumour diameters because of changes in vascular supply and necrosis in its centre. The effects these parameters may have on the therapeutic results are expressed by different penetration depth of light at different tumour diameters [52]. Due to the changing optical properties resulting from increased tumour diameter, dosimetry needs to be adapted to achieve proper and comparable results after PDT.…”

“…Due to the changing optical properties resulting from increased tumour diameter, dosimetry needs to be adapted to achieve proper and comparable results after PDT. In other words, an increasing tumour diameter requires an increasing treatment time of a standardized light dose, depending on its correction factor [52].…”

“…Based on the findings of optical parameters and considering all the abovementioned aspects, a very simple and save dosimetry formula was developed and approved in clinical practice of more than 300 esophageal PDT's by Maier et al [52]. The dosimetry formula is based on the use of a standardized light applicator of different length and includes the following variables: (1) diameter of the tumour stenosis and distance of the irradiation source from the tumour surface, (2) length of the irradiation source and appropriate light applicator system, (3) optical parameters of esophageal carcinoma and (4) desired light dose (J/cm 2 ).…”