Combined Laser-Induced Hyperthermia/Photodynamic Therapy System

Photodynamic Therapy (PDT) using Photofrin is nearing regulatory approval both in the U. S. A. and abroad. It has been shown by a number of researchers that hyperthermia (HT), less than 45 degrees centigrade, has a strong synergistic effect in combination with PDT. This synergism appears to be maximized when the HT is given concurrently with PDT instead of sequentially. It has also been shown that the local hyperthermia condition can be produced by a near infrared laser, Nd:YAG or AlGaAs diodes, through the same delivery systems used for PDT. This has been referred to as Laser Hyperthermia, or LHT. It is our objective to develop an integrated LHT-PDT delivery system with a common computer-based control and monitoring system. The system will allow for use of pre-existing lasers, both HT and PDT, which are delivered to the system via fiberoptic cables. Each laser is to be individually controlled and combined into a single optical delivery fiber. The control system is to be based on a PC compatible computer and will provide active control of the LHT and PDT power levels, treatment intervals, monitoring and display of eight temperatures and four light intensity levels, tissue temperature stabilization, light dosimetry, and display the information in a user friendly manner. The emphasis in Phase I is to develop the system, and to test it in an appropriate animal model.