Computer-aided dynamic simulation of microwave-induced thermal distribution in coagulation of liver cancer

To develop a method of dynamic three-dimensional (3-D) simulation of therma l distribution in ultrasound-guided microwave coagulation therapy of liver cancer and to verify its accuracy. The specific absorption rate (SAR) value s were established by measuring the temperature in equivalent phantom tests . Those values were different under different power output condition. Dynam ic 3-D temperature distributions were reconstructed with a finite-element m odel. Testing and rectification were performed through animal experiments a nd clinical trials, respectively. The temperature curves in the experiments corresponded well with simulated ones in vitro - 91.4% and 88.9% using sin gle and double electrodes, respectively. The measured coagulated boundary a nd simulated temperature boundary had a good correspondence in 85.7% of the specimens. In both in vivo experiments and clinical trials, blood perfusio n influenced the rise in temperature significantly. Temperature curves betw een the simulations and actual measured results showed good correspondence (67.8% (19/28) in the patients with hepatocellular carcinoma. Distance betw een electrodes and combined thermal distributions were both optimized with computer-aided simulation during simultaneous two-electrode coagulation. Th e results demonstrated that computer-aided simulation of microwave thermal distribution is an accurate and reliable method which provides a theoretica l and technical basis for controlling coagulated tissue volume and placemen t of the electrodes during microwave coagulation therapy of liver cancer.