The long-term objective of the proposed program is to develop instrumentation that can safely and effectively treat benign prostatic hypertrophy [BPH] in a single session without the use of anesthesia. The proposed instrumentation combines microwave heating with balloon dilation to produce long-lasting biological stents in the urethra. The safety of the procedure is assured by controlling the applied microwave power with thermocouples and with a microwave radiometer that can non-invasively measure temperature profiles in the treated prostate gland. During Phase I instrumentation suitable for animal trials was developed and tested in tissue equivalent phantoms. In post Phase I experiments, the prostates of four dogs were dilated and heated with microwaves to therapeutic temperatures. The rectums of all dogs remained at all times at safe temperatures. A patent prostatic urethra [biological stent] with a diameter 6mm was measured in the dissected prostate of one dog. During the proposed Phase II program, instrumentation and treatment protocols will be optimized in experiments using 20 dogs, and instrumentation suitable for future use in clinical trials will be fabricated. PROPOSED COMMERCIAL APPLICATIONS: The proposed approach for treating BPH is expected to be safe, effective, lower in cost, and produce fewer side effects than current approaches. Because of these advantages, it should find wide acceptance by urologists and patients. The treatment is covered by a US patent issued to the Principal Investigator and assigned to MMTC, Inc. Microwave radiometers that are covered by patents issued to the Principal Investigator and assigned to MMTC, Inc. will also be incorporated into the system.