A Double Iteration Greedy Heuristic Approach for Permanent Brachytherapy Planning

Abstract

This paper presents a double iteration greedy heuristic (DIGH) approach for permanent brachytherapy treatment planning. The DIGH approach adopts a greedy heuristic seed selection (GHSS) procedure to obtain a preliminary plan. In this process, the potential seeds are evaluated according to their ability to irradiate target volume while sparing organs-at-risk (OARs). Their impact on dosimetric homogeneity within target volume is also taken into account. The preliminary treatment plan generated by the GHSS procedure is further refined by the double iteration (DI) procedure. The DI procedure removes the needles containing only one seed (single seed) and implements the GHSS procedure again to obtain a temporary plan. The DI procedure terminates when the needle number of the temporary plan does not decrease. This process is guided by constantly removing the undesired part rather than imposing extra constrains. The efficiency and robustness of the DIGH approach is tested on three kinds of typical patient cases. For these cases, treatment plans are generated in less than 30s. The dosimetric distribution of these treatment plans achieves satisfactory dosimetric distribution. The numbers of used needles are kept within acceptable level. The experimental results demonstrate that the DIGH approach is fast, effective and robust. It has the potential to be used for intraoperative brachytherapy treatment planning in operation room.