Fast GPU Computation of 3D Isothermal Volumes in the Vicinity of Major Blood Vessels for Multiprobe Cryoablation Simulation

Percutaneous cryoablation is a minimally invasive procedure of hypothermia for the treatment of tumors. Several needles are inserted in the tumor through the skin, to create an iceball and kill the malignant cells. The procedure consists of several cycles alternating extreme freezing and thawing. This procedure is very complex to plan, as the iceball is formed from multiple needles and influenced by major blood vessels nearby, making its final shape very difficult to anticipate. For computer assistance to cryoablation planning, it is essential to predict accurately the final volume of necrosis. In this paper, a fast GPU implementation of 3D thermal propagation is presented based on heat transfer equation. Our approach accounts for the presence of major blood vessels in the vicinity of the iceball. The method is validated first in gel conditions, then on an actual retrospective patient case of renal cryoablation with complex vascular structure close to the tumor. The results show that the accuracy of our simulated iceball can help surgeons in surgical planning.