宫颈癌患者放疗中期二次计划的剂量学优势  

Dosimetric advantages of secondary plan at mid cervical cancer radiotherapy

作　　者：雷怀宇 张书旭[1] 林生趣[1] 余辉[1] 周露[1] 蒋绍惠 周祥[1] 

机构地区：[1]广州医科大学附属肿瘤医院放疗中心,广东广州510095

出　　处：《中国医学物理学杂志》2015年第5期686-689,共4页Chinese Journal of Medical Physics

基　　金：广东省教育厅特色创新项目(自然科学类)(2014KTSCX104);广州市医药卫生科技项目(20131A011165)

摘　　要：目的:探讨宫颈癌调强放疗患者放疗中期二次计划的剂量是否与单次计划存在差别。方法:选择20例行宫颈癌调强放疗的患者,放疗中期再次行CT定位扫描,并制定放疗计划,将初始放疗计划的剂量形变到再次定位CT上,得到形变计量体积直方图(Dose-Volume Histogram,DVH),将形变DVH与二次计划的DVH叠加,得到叠加DVH,比较初始DVH与叠加DVH中靶区及正常组织的剂量。结果:(1)二次计划与单次计划相比,临床靶区(CTV)的靶区覆盖率(Conformity Index,CI)和均匀性指数(Homogeneity Index,HI),无统计学差异(P>0.05),计划靶区(Planning target volume,PTV)的CI和HI有统计学差异(P<0.05);(2)二次计划与单次计划相比,CTV的Dmean,PTV的D100、D95、Dmean均有统计学差异(P<0.05),CTV的D100、D95、D90,PTV的D90均无统计学差异(P>0.05);(3)二次计划与单次计划相比,膀胱的V50、Dmean,直肠的V50、Dmean有统计学差异(P<0.05);膀胱的V40、V30,直肠的V45、V40,股骨头的V50、V40、V30、Dmean无统计学差异(P>0.05)。结论:宫颈癌调强放疗患者放疗中期二次计划,能提高PTV的CI和HI,减少PTV和CTV覆盖剂量的不足;能减少直肠和膀胱的受量;对股骨头的受量变化无影响。Objective To investigate the dosimetric difference between a secondary plan at mid radiotherapy and a single plan for cervical cancer. Methods Twenty patients received intensity modulated radiation therapy （IMRT） for cervical cancer were selected. The CT location scan and radiotherapy plan were underwent again at mid radiotherapy. The dosage of initial plan was deformed to the secondary CT to obtain a deformation dose volume histogram （DVH）. A superposition DVH was obtained by superimposing the deformation DVH and the DVH of secondary plan. The dosages in target volumes and normal tissues of initial DVH and superimposing DVH were compared. Results Compared with a single plan and secondary plan, no statistical differences were found in the conformal indexes （CI） and homogeneity index （HI） of clinical target volume （CTV） （P〉0.05）, but the statistical differences were found in the CI and HI of planning target volume （PTV） （P〈0.05）. There was no statistical differences in D100, D95, D90 of CTV and D90 of PTV （P〉0.05）, but there were statistical differences in Dmean of CTV, D100, D95, Dmean of PTV （P〈0.05）. Moreover, no statistical differences were found in V40, V30 of bladder, V45, V40 of rectum, V50, V40, V30, Dmean of femoral head （P〉0.05）, however, the statistical differences were found in the V50, Dmean of bladder and V50, Dmean of rectum （P〈0.05）. Conclusion The secondary plan at mid cervical cancer radiotherapy can improve the CI and HI of PTV, reduce the insufficiency of dosage in PTV and CTV, and reduce the dosage in rectum and bladder, without affecting the dosage in femoral head.

关 键 词：宫颈癌 调强放疗 二次计划 剂量 

分 类 号：R730.5[医药卫生—肿瘤]