Focused Extracorporeal Pyrotherapy: Feasibility Study in Man

A feasibility study of focused extracorporeal pyrotherapy was conducted in 50 patients. The instrument has a mobile Firing head, which is composed of multiple piezoelectric ceramics with a focal length of 320 mm. The energy focus was 10 mm high × 1.5 mm wide. A retractable and rotating central 3.5-MHz ultrasound transducer was used to localize the tissue target. A 7.5-MHz sectorial transrectal transducer was used for the prostate. The recording of the temperature curves by means of implanted thermocouples demonstrated that the apparatus was able to induce a peak temperature of 120°C in the focal zone. Heat diffusion was minimal because of the brief shot durations (0.015 to 1 second). Twenty-eight patients with benign prostatic hyperplasia were treated. There was virtually no heat diffusion to the rectum and urethra. The maximum temperature recorded in 12 patients who underwent pyrotherapy for superficial bladder tumors was 65°C. Eight patients underwent the same treatment to the kidney, and two patients w...