| 李毅,陈鑫,李文荣,张晓智.子野权重优化在宫颈癌术后IMRT计划中的应用研究[J].中华放射医学与防护杂志,2013,33(6):619-622 |
| 子野权重优化在宫颈癌术后IMRT计划中的应用研究 |
| Application of SWO technique in IMRT plan of post-operative cervical cancer |
| 投稿时间：2013-05-06 |
| DOI：10.3760/cma.j.issn.0254-5098.2013.06.013 |
| 中文关键词: 子野权重优化 宫颈癌 调强放疗 |
| 英文关键词:Segment weight optimization Cervical cancer Intensity modulated radiation therapy |
| 基金项目: |
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| 摘要点击次数: 3303 |
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| 中文摘要: |
| 目的 探讨子野权重优化（SWO）技术对宫颈癌根治术后调强放疗（IMRT）计划总子野数、总机器跳数（MU）、靶区均匀性指数（HI）、适形度指数（CI）以及靶区和正常组织照射剂量的影响。方法 随机抽样选取10例接受根治术后的Ⅰ~Ⅱ期宫颈癌患者，应用ELEKTA XIO 4.62系统，采用相同的射野方向和优化参数，利用静态调强（Step & Shoot）的传统方法优化，作为S-IMRT计划；同时，应用SWO对IMRT计划做进一步的优化，作为SWO-IMRT计划。比较子野权重优化前后总子野数、总MU数的变化，同时利用剂量体积直方图（DVH）评价靶区均匀性指数（HI）、适形度指数（CI）以及靶区和正常组织照射剂量。结果 与S-IMRT计划比较，SWO-IMRT计划的平均子野数由（96±4）个降至（87±4）个（t=10.049，P<0.05）；MU数由（638.79±35.02）cGy增至（672.03±39.07）cGy（t=3.952，P<0.05）；计划靶区（PTV）最大剂量（Dmax）和平均剂量（Dmean）降低（t=2.262、2.323，P<0.05）；脊髓最大剂量（Dmax）由（3856.00±112.14）降至（3750.00±141.38）（t=3.976，P<0.05）；SWO-IMRT计划膀胱V30、V40、V50，直肠V30，左侧股骨头V50的剂量低于S-IMRT计划（t=4.223、5.801、7.534、2.451、2.269、3.976，P <0.05）；对于靶区剂量均匀性指数（HI）、适形度指数（CI）、直肠V40、V50，左侧股骨头V30、V40、V50，右侧股骨头V40、V50，差异无统计学意义。结论 SWO技术应用于宫颈癌根治术后IMRT计划中，总子野数减少，总MU数增加，脊髓和膀胱剂量降低。既降低了脊髓和膀胱的不良反应，也为肿瘤剂量的提高提供了可能。SWO技术为临床工作提供了一种可选择的优化工具。 |
| 英文摘要: |
| Objective To investigate the impact of segment weight optimization(SWO) technique on the intensity modulated radiation therapy(IMRT) plan for post-operative cervical cancer regarding the number of segments,monitor units(MU), the target homogeneity index(HI), conformal index(CI) and dose distribution of target volume and normal tissues. Methods Ten patients with stage Ⅰ and Ⅱ cervical cancer after radical resection were randomly selected for this study. The initial IMRT treatment plans were generated using ELEKTA XIO 4.62 system based on the step and shoot method (S-IMRT plan). With the same directions of fields and optimization parameters, the SWO tool was introduced to optimize the IMRT plans further (SWO-IMRT plan). Then the number of segments and MU were compared between the S-IMRT plan and SWO-IMRT plan. By using the dose-volume histogram (DVH), the target homogeneity index (HI), conformal index (CI) and dose distribution in the volumes of target and normal tissues were also analyzed. Results Compared with S-IMRT plan, the average number of segments in SWO-IMRT plan was decreased from 96±4 to 87±4(t=10.049, P<0.05), and MU was increased from(638.79±35.02)) to (672.03±39.07) (t=3.5952, P<0.05). The maximum and mean doses of the planning target volume (PTV) decreased (t=2.262, 2.323,P<0.05). A reduction of the maximum dose in the spinal cord was also observed [from (3856.00±112.14) cGy to (3750.00±141.38) cGy, t=3.976, P<0.05]. The values of V30,V40,V50 in bladders, rectal V30 and L-femoral V50 were reduced in the SWO-IMRT plan (t=4.223, 5.801, 7.534, 2.451, 2.269, 3.976, P<0.05). However, there was no significant difference in target homogeneity index(HI),conformal index(CI),rectal V40,V50,L-femoral V30,V40,V50, R-femoral V40 and V50. Conclusions The application of SWO technique in the IMRT planning for cervical post-operative cancer could reduce the total number of segments, doses in the spinal cord and bladder, but increase the total number of MU. As a result, the spinal cord and bladder toxicity can be reduced which enables an opportunity for dose escalation of gross tumor volume (GTV). SWO technique provides clinicians with an optional optimization solution in IMRT plan for post-operative cervical cancer patients. |
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