Project Summary: The primary objective of this proposed research program is to evaluate in a clinical trial the improvements to clinical outcomes that the use of a software for supporting physicians during the percutaneous microwave ablation of liver tumors can result in. In percutaneous microwave ablation a needle-shaped ablation probe is inserted in the tumor by entering the body through the skin. The tip of the probe can emit microwaves and heat the tissues, killing a certain volume of tissues around the tip of the probe. The goal is to kill completely the tumor by performing a single ablation, for smaller tumors, or by placing the probe at multiple positions and performing multiple ablations that cover all the tumor volume. During the procedure the patient lies in a CT scanner and several images are acquired to visualize the position of the probe and of the tumor. It is challenging though for physicians to evaluate from these images which part of the tumor has been killed and which not – as a consequence, the procedure might be terminated early thinking that all malignant tissues have been treated, while small portions of the tumor are in practice left untreated. Depending on the tumor size this can happen in 20% (medium tumors) to 50% (large tumors) of cases. NE Scientific has developed a software which is able to simulate the physics taking place during the procedure and to determine which tissues are killed based on the simulations. The killed tissues, estimated based on the simulation, are highlighted on the CT images during the procedure, so that the physician always know which part of the tumor might still need to be killed. This computerized aid to physicians should result in a much lower rate of incomplete ablations. The trial part of this program will monitor the rate of tumor recurrence (arising from incomplete ablations) in 84 patients which will undergo microwave ablation for treating liver tumors. If the trial is successful, microwave ablation, combined with computerized guidance, will be a minimally invasive cancer treatment option which does not present the side effects of chemotherapy and radiotherapy.