RapidArc在晚期肝门区胆管癌放疗中的物理剂量学探讨

Dosimetric study of RapidArc for advanced hilar cholangiocarcinoma in radiotherapy

【目的】研究快速旋转调强(RapidArc)在晚期肝门区胆管癌放疗中的适用性。【方法】利用瓦里安Eclipse 10.0计划系统设计晚期肝门区胆管癌患者RapidArc计划10例;利用剂量体积直方图(dose-volume histogram,DVH)分析靶区的相关剂量学参数以及危及器官(organs at risks,OARs)的评价指标;利用PTW电离室矩阵和EPID-Portal Dosimetry系统进行计划验证;利用OBI系统保证治疗中的位置精度。【结果】计划靶区体积(planning target volume,PTV)的D2、D98、Dmean分别为:(48.94±0.88)Gy,(52.74±0.95)Gy,(51.45±0.92)Gy,适形指数(conformity Index,CI)为(0.95±0.09),有较好的适形度。OARs指标均在较低的水平;2种验证方法的γ通过率均在95%以上;治疗时的位置精度均在±3 mm以内。【结论】RapidArc能够满足晚期肝门区胆管癌放疗的临床剂量学要求。

[Objective] To study the applicability of RapidArc for advanced hilar cholangiocarcinoma in radiotherapy. [Methods] Varian Eclipse 10.0 treatment planning system was used to design the RapidArc treatment for 10 cases with advanced hilar cholangiocarcinoma. Related dosimetric parameters in the target area and indexes of organs at risk （OARs） were analyzed via dosevolume histograms （DVH）. The PTW Array and EPID-Portal Dosimetry system were used to verify these plans. Positional accuracy in the treatment was ensured by OBI system. [Results] The D2,D98 and Dmean of planning target volume （PTV） were respectively （48.94±0.88） Gy, （52.74±0.95） Gy and （51.45±0.92） Gy; CI was 0.95±0.09 and the indexes of PTV were of better conformity. The indexes of OARs were all in lower levels; the γ pass rates of the two methods were both more than 95%; the positional accuracy of the treatment was within ＋ 3mm. [Conclusion ] RapidArc can meet the clinical dosimetry requirements in radiotherapy for advanced hilar cholangiocarcinoma.