Photodynamic therapy alone or in conjunction with near-infrared light-induced hyperthermia in human malignant tumors. a methodological case study

Several relevant physical parameters, such as superficial blood perfusion, temperature rise and tumor fluorescence characteristics, were monitored in an attempt to perform well-controlled photodynamic thera-py (PDT) on several human malignant tumors. DHE (Photofrin TT) was used as a photosensitizer at a concentration of 2 mg/kg b.w. administered i.v. 48-120 hours before treatment. 630 nm radiation from a CW dye laser, normally at an energy dose of 60 J/c10, at a dose rate well below the hyper-thermal region was delivered to seven 1-4 mm thick basal cell carcinoma lesions. PDT and near-infrared light-induced hyperthermia were performed simultaneously on six 5- 10 mm thick lesions of recurrent breast cancer in another patient. A filtered slide projector running at a power of about 200 mW/c1.0 with radiation above 665 nm was used for the light-induced hyperthermia. All the tumors were eradicated. PDT parameters and tissue temperature recordings were used as input data for an analytical PDT/hyperthermia model. The measured parameters have to be supplemented with assumed values for several other parameters. Although highly qualitative the model provides some interesting insight into the relative importance of PDT and hyperthermia.