宫颈癌调强放疗膀胱限制剂量研究

A study of bladder restricted dose in pelvic IMRT plan of cervical cancer

目的通过分析不同调强计划膀胱体积剂量,探讨合适的膀胱体积剂量限制参数。方法以膀胱D40<40 Gy(计划一)及D2cc<49 Gy(计划二)分别设计调强计划,靶区及其余危及器官限制条件相同,比较两个调强计划膀胱各水平体积(90%、70%、50%、40%、30%、10%、2cc)剂量D90、D70、D50、D40、D30、D10、D2cc、膀胱最大剂量Dmax、平均剂量Dmean及靶区和其余危机器官剂量。结果计划一与计划二PTV及除膀胱外OARs体积剂量均无显著差异(P>0.05),计划一膀胱D90、D70、D50较计划二低,分别为(10.1±0.4)Gy vs(12.0±0.6)Gy、(20.2±0.7)Gy vs(21.9±0.9)Gy、(30.2±1.1)Gyvs(30.7±1.2)Gy,(P均<0.05)。计划一膀胱D30、D10、D2cc、Dmax较计划二高,分别为(43.0±0.6)Gy vs(42.6±0.5)Gy、(46.7±0.7)Gy vs(45.9±0.8)Gy、(49.1±0.4)Gy vs(48.5±0.2)Gy、(49.7±0.3)Gy vs(49.3±0.3)Gy(P均<0.05)。两个计划膀胱D40及Dmean相似,分别为(38.5±0.9)Gy vs(38.4±1.0)Gy、(38.7±0.7)Gy vs(38.8±0.7)Gy,(P均>0.05)。结论 D2cc替代D40作为膀胱的限制剂量参数具有临床可行性,且为靠近靶区的膀胱壁组织提供了更好的剂量学保护。

Objective To discuss the appropriate restricted dose of bladder in pelvic intensity-modulated radiotherapy （IM- RT） for patients with cervical cancer. Methods Two pelvic IMRT plans were designed using the restricted condition, D4o〈 40 Gy （plan 1） and D~〈49 Gy （plan 2） of bladder, and the same restricted condition for planning target volume （VI＇V） and other organs at risk （OARs） for each patient espeetively. The bladder D9o, D7~, Dx~ D~, Dn, D^e, D~,,, D~, D~, of two IMRT plans for each patient were compared espectively. The dose distributions of PTV and other OARs were compared either. Results There was no significant difference of dose distributions of PTV and other OARs between two IMRT plans. The bladder D90, DTe, D, D D3e, Dlo, D2, D, D. of plan 1 vs plan 2 were （10.1＋0.4） Gy vs （12.0_＋0.6） Gy, （20.2_＋0.7） Gy vs （21.9_＋0.9） Gy, （30.2_＋1.1） Gy vs （30.7_＋1.2） Gy, P = 0.002, （38.5-＋0.9） Gy vs （38.4-＋l.0） Gy, （43.0_＋0.6） Gy vs （42.6_＋0.5） Gy, （46.7_＋0.7） Gy vs （45.9_＋0.8） Gy, （49.1±0.4） Gy vs （48.5±0.2） Gy, （49.7±0.3） Gy vs （49.3±0.3） Gy, （38.7±0.7） Gy vs （38.8±0.7） Gy, respectively. Bladder D DT, Dso of plan 1 were lower than those of plan 2. Bladder D,D10, D, D, D of plan 1 were higher than those of plan 2 inversely. There was no significant difference between the D40 and D,~, of bladder. Conclusion Bladder D. was a feasible restricted condition for pelvic IMRT design of cervical cancer. Bladder wall nearby the target volume could benifit from the dose distribution of IMRT plan designed with the restricted condition of bldder D