A system and method are disclosed for thermal therapy that takes into account predictive calculations of tissue temperature, and can be used to control the operation of a conformal thermal therapy procedure and device. In some embodiments, the tissue ablation area is part or all of a prostate gland. The method includes, in preferred embodiments, simulations and or calculations of future temperatures based on some or all of the following information: current temperatures, heat diffusion in the tissue, blood perfusion in the tissue, and planned ultrasound energy depositions. The calculated temperature maps can be used to design, control, or terminate the therapy.