巨块肝癌分靶区计划设计与评估

Designing and evaluating the treatment plans using divided targets for stereotactic body radiotherapy of massive liver cancer tumors

目的为了提高肿瘤的覆盖率,减小漏照体积,探讨对巨块肝癌分靶区治疗计划进行设计。方法选取巨块肝癌2例,首先把计划靶区(PTV)作为一个靶区进行计划设计;然后进行分靶区计划设计,把PTV分成3个子靶区,分别为PTV1、PTV2和PTV3。PTV1和PTV3为计划设计区,PTV2是PTV1与PTV3之间的间隔区。然后对这两种方法设计出来的结果进行对比和评估。结果分靶区与单靶区计划设计相比,两个病例的肿瘤覆盖率分别提高了15.94%和32.49%,靶区的漏照射体积减少135.78cc(78.20%)和227.37cc(97.02%)。结论分靶区计划设计的方案解决了巨块肝癌计划设计困难和边缘剂量不足的问题,大大提高了肿瘤的覆盖率。分靶区计划设计增加了患者的治疗次数,延长了治疗时间。

[ Objective ] In order to improve coverage to tumors and decrease the mis-irradiated volume, we discussed the design of using divided targets for the treatment of massive liver cancer tumors. [ Methods ] We selected two cases of massive liver cancer.At first, we used the PTV1 as a single target for the treatment; then we used the divided targets for the treatment plan.We divided the planning target volume （PTV） into three sub-targets： PTV1, PTV2 and PTV3.The PTV1 and PTV3 were the regions for which treatment plans were designed, and the PTV2 was the spacer region between PTV1 and PTV3.For both methods, we compared and evaluated the results ofthem. [ Results ] Compared with the plans for a single target, the plans for divided targets increased 15.94% and 32.49% of the tumor coverage for two cases, respectively. The mis-irradiated volume in the target area decreased 135.78 cc （73.77%） and 227.37 （97.02%）. [ Conclusion ] Plans that used divided targets overcame the challenge of designing treatment plans for massive liver cancer tumors, and resolved the problem of dose shortage to the edge of tumor.These plans greatly improved tumor coverage, however, increased the treatment time for patients.