巨块肝癌分靶区与单靶区计划设计对比

目的：为了提高肿瘤的覆盖率，解决靠近敏感器官的肿瘤边缘剂量不足的问题，探讨对巨块肝癌进行分靶区治疗计划设计。方法：在治疗计划设计时把计划靶区（PTv）分成三个子靶区，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。选取2例巨块肝癌病例，采用相同的处方剂量和敏感器官限量，分别采用单靶区和分靶区进行计划设计，然后对这两种方法设计出来的结果进行对比和评估。结果：病例1，单靶区和分靶区计划设计下的肿瘤覆盖率分别为66．51％和99．00％。病例2，单靶区和分靶区计划设计的肿瘤覆盖率分别为56．85％和92．00％。结论：病例1和病例2通过分靶区计划设计，肿瘤覆盖率分别提高了32．49％和35．15％。分靶区计划设计大大提高了肿瘤的覆盖率，但增加了患者的治疗次数，延长了治疗时间。

Designing Treatment Plans Using Divided Targets for Stereotactic Body Radiotherapy of Massive Liver Cancer Tumors

Objective： In order to improve coverage to these tumors and resolve the problem of dose shortage to the tumor edges that are near organs at risk （OARs）, we designed treatment plans using divided targets for stereotactic radiotherapy of massive liver cancer tumors.Methods： We divided the planning target volume （PTV） into three sub-targets when designing treatment plans： PTV1, PTV2 and PTV3. The PTV1 ~/nd PTV3 were the regions for which treatment plans were designed, and the PTV2 was the spacer region between PTV1 and PTV3. We selected two cases of massive liver cancer and adopted the same prescribed dose and dose threshold for OARS for both cases. For each of these two cases, we designed one-plan for a single target and a second plan for divided targets. We then compared and evaluated the results of these two plans. Results： For Case 1, the tumor coverage rates in single-target plan and in divided-targets plan were 66.51% and 99.00%, respectively. For Case 2, the coverage rates in single-target plan and in divided-targets plan were 56.85% and 92.00%, respectively.Conclusious： Because of the divided-targets plan, the tumor coverage of Case 1 and Case 2 improved 32.49% and 35.15%, respectively. The method of divided-targets plan greatly improved tumor coverage. However, it also increased treatment time for patients.