Treatment Planning and Image Guidance for Radiofrequency Ablation of Liver Tumors

摘要

Radiofrequency ablation is becoming an increasingly attractive option for minimally invasive treatment of liver tumors. In this procedure, the tumor and its margin are ablated using radiofrequency ablation probes that cover a region from 2cm to 7cm in diameter. For a large or irregularly shaped tumor, multiple ablations with overlapping probe placements are required. In this paper, we propose a treatment planning system to optimize these placements. A general optimization framework based on inverse planning methods is designed to generate the treatment plan. An objective function is defined to describe the coverage of the ablation volumes. Powell's method and simulated annealing algorithms are used to find the solution. Pre-computed mask volumes and an initial placement based on a Euclidean Distance Transform are used to speed up the computation, which can generally take a few seconds to several minutes. To ensure accurate placement of the ablation probe, we also propose a system architecture for integrating the treatment planning system with our previously developed image-guided surgery system, which uses an electromagnetic tracking device. We present some preliminary results from synthetic data to validate our treatment planning algorithm and system concept.