The extend of necrosis caused by TUMT treatment depends on the temperatures created in the prostate, and the amount of time that the tissue is exposed to those temperatures. This relationship is the bio-heat equation and is vital in determining when thermal treatments are effective.

Thermal dose cannot be reliably predicted solely on the basis of microwave energy applied, since the actual intra-prostatic temperatures achieved also depend on the efficiency of both energy transfer and conversion to heat within the target tissue. _{(Bob Djavan, MD, PhD and Michael Marberger, MD, "Minimally Invasive Procedures and Medical Management—Their Relative Merits in Treating Lower Urinary Tract Symptoms of Benign Prostatic Hyperplasia" Reviews in Urology. 2000 Spring; 2(2): 105–114 )}

Critical variables affecting achieved intra-prostatic temperatures include the ability of the microwave antenna to be “tuned” for maximum energy transfer into prostatic tissue, the efficiency of the antenna in delivering microwave energy with minimum loss, the histologic composition of the individual patient’s prostate gland, and the capacity of the prostate gland to dissipate heat via changes in blood flow. _(ibid)