METHODS: Twenty patients of carcinoma cervix FIGO Stage IIIB treated with concurrent chemoradiotherapy were selected for this study. The external contour of bones was delineated on planning CT as a surrogate for BM. We generated three plans on a single patient:1. without BM as the dose constraint, namely N-IMRT plan; 2. with BM constraint, namely BMS-IMRT plan; 3. VMAT plan in which BM constraint was given. The dose volume histogram (DVH) for planning target volume (PTV) and organs at risk (OAR) were analyzed. BM parameters: V10, V20, V30, V40, mean, maximum and minimum dose were compared. Results: PTV coverage was comparable in all techniques. VMAT plans resulted in superior BM sparing compared with N-IMRT plan (P-<0.001) and BMS-IMRT plan (P-<0.001, 0.021 and 0.001 respectively for V20, V30 and V40). VMAT plans had better CI compared with BMS-IMRT (P-0.002) and N-IMRT (P-0.001) plans.
CONCLUSIONS: Our study adds to the growing evidence that VMAT might be the preferred technique for patients with carcinoma of the cervix undergoing concurrent chemoradiotherapy, as it provides comparable target coverage and better sparing of bone marrow compared to IMRT.
方法:选择同期放化疗治疗的20例宫颈癌FIGOIIIB期患者进行本研究。在计划CT上描绘了骨骼的外部轮廓,作为BM的替代。我们对单个患者产生了三个计划:1.没有BM作为剂量约束,即N-IMRT计划;2.使用BM约束,即BMS-IMRT计划;3.给出BM约束的VMAT计划。分析了计划目标体积(PTV)和危险器官(OAR)的剂量体积直方图(DVH)。BM参数:V10,V20,V30,V40,平均值,比较最大和最小剂量。结果:所有技术的PTV覆盖率均具有可比性。与N-IMRT计划(P-<0.001)和BMS-IMRT计划(V20,V30和V40分别为P-<0.001、0.021和0.001)相比,VMAT计划导致更好的BM节省。与BMS-IMRT(P-0.002)和N-IMRT(P-0.001)计划相比,VMAT计划具有更好的CI。
结论:我们的研究增加了越来越多的证据,表明VMAT可能是接受同步放化疗的宫颈癌患者的首选技术,与IMRT相比,它提供了可比的目标覆盖率和更好的骨髓保护。