Real‐time tissue change monitoring during the treatment of prostate cancer using Sonablate 500 with high intensity focused ultrasound.

Abstract

Tissue change monitoring (TCM) during HIFU is an essential required feedback during the HIFU treatment. The Sonablate 500 (SB500) HIFU is enhanced with quantitative, real‐time TCM software that estimate changes in tissue properties due to HIFU treatment of prostate cancer. TCM generates energy reading based on spectral analysis of the two‐dimensional rf backscattered ultrasound signals acquired during HIFU. These energy changes are correlated to tissue temperature. TCM results are overlaid on the real‐time ultrasound image in green, yellow, and orange to represent low, medium, and high degree of change in backscattered energy levels. To validate the TCM process five patients with histologically confirmed, organ confined prostate cancer were enrolled for the study. Needles containing three thermocouples were placed transperineally under TRUS guidance in the prostate to monitor temperatures from focal zone, posterior to the focal zone and on the lateral gland where no HIFU was applied. The measured temperatures in the HIFU treatment zones were from 70–114 °C (average 84 °C). The TCM results, estimated tissue temperatures were from 75 to 100 °C for 83% of treatment sites with an average tissue temperature of 91 °C.