AN ACCURATE TECHNIQUE FOR DETAILED PROSTATIC INTERSTITIAL TEMPERATURE-MAPPING IN PATIENTS RECEIVING MICROWAVE THERMAL-TREATMENT

A minimally invasive prostatic interstitial temperature-mapping techni que is described that supplies accurate, detailed information on therm al doses delivered to precisely localized tissue sites, The technique employs a comparatively large numbers of thermosensors, highly accurat e placement of those thermosensors at specified three-dimensional coor dinates, fiberoptic technology that avoids significant interaction bet ween the thermosensors and the applied microwave field, and continuous temperature readout, Biplane ultrasound imaging and fluoroscopy were used to ensure stereotactic accuracy of thermosensor placement, The te chnique was applied in 15 patients with benign prostatic hyperplasia ( BPH) undergoing a 1-hour microwave thermal treatment session, The ther mal mapping procedures and microwave treatment were generally well tol erated, The mean maximum temperature in the prostate and periprostatic tissue (57.9 +/- 1.9 degrees C) was significantly higher (P < 0.001) by more than 18 degrees C than that in either the urethra (39.6 +/- 0. 9 degrees C) or the rectum (40.8 +/- 1.7 degrees C), In a representati ve patient, microwave treatment resulted in stable elevation of temper ature 5 mm radially from the urethra that averaged 66.0 +/- 0.1 degree s C, At 10 mm from the urethra, the temperature averaged 50.5 +/- 0.1 degrees C, Urethral and rectal temperatures remained at innocuous leve ls, In conjunction with pathologic studies, this interstitial thermal mapping method should prove useful in defining the optimal thermal dos es for microwave therapy, The method should also find uses in evaluati ng different microwave treatment systems, which can vary markedly in t hermal performance, as well as other modalities that apply heat to pro static tissue.