Mathematical Modeling and Simulation of Laser-Induced Thermotherapy for the Treatment of Liver Tumors

Laser-induced thermotherapy (LITT) plays an important role in oncology to treat human liver tumors. LITT is an alternative method which is used when surgery is too dangerous for the patient. It is a minimally invasive method causing tumor destruction due to heat ablation and coagulative effects of the tissue. The big advantage of the LITT compared to other minimally invasive procedures is that the treatment takes place under MRI control, such that patients are exposed to a small radiation dose. Based on temperature-sensitive magnetic resonance parameters, it is feasible to monitor the tissue temperature during cancer treatment (MR thermometry). Combining both MR thermometry and mathematical simulation is a promising procedure to identify temperature-dependent tissue parameters and to optimize the cancer treatment. The present paper describes the mathematical modeling of the laser-induced thermotherapy. The well-known Pennes bioheat equation is coupled with the radiative transfer equation which describes the energy gain of the tumor tissue. It is shown, that the modeling of vaporization is important to match mathematical simulation with temperature measurements for ex-vivo porcine liver.