Evaluation of three temperature measurement methods used during microwave thermotherapy of prostatic enlargement

Abstract

Three temperature measurement methods used during microwave thermotherapy of prostatic enlargement are analysed and evaluated using a phantom model. A commercial transurethral microwave thermotherapy (TUMT) system that uses a radiometric thermometer for temperature control was used to heat the phantom. The transient temperature distribution was obtained by using both fibreoptic (which is considered as gold standard) and thermocouple measurements. Both methods are subject to potential measurement errors caused by electromagnetic and/or thermal interference. The error sources are analysed and the measurement methods evaluated. The radiometric temperature and especially its relation to the transient temperature distribution was evaluated based on the fibreoptic and thermocouple measurements. These measurements in principle gave equivalent temperature distributions, and thermal interference was concluded to be the largest source of measurement error. The radiometric measurement method gave qualitative rather than quantitative readings of the temperature, and an underestimation of more than 10°C was obtained for some parts of the heated area. The area that gives most of the radiometric signal was relatively close to the catheter in contrast to previously published results.

• Temperature measurement
• temperature distribution
• thermocouple
• fibreoptic
• radiometric thermometry
• prostate.