| 张建平,王琳,徐本华,黄妙云,陈远贵,李文尧,李小波.新适形指数对肺癌立体定向放疗治疗计划质量的影响[J].中华放射医学与防护杂志,2018,38(6):424-428 |
| 新适形指数对肺癌立体定向放疗治疗计划质量的影响 |
| Effects of the new conformity index on planning quality of lung cancer SBRT |
| 投稿时间：2017-12-01 |
| DOI：10.3760/cma.j.issn.0254-5098.2018.06.005 |
| 中文关键词: 周围型肺癌 立体定向放射治疗 常规适形指数 新适形指数 |
| 英文关键词:Peripheral lung cancer Stereotactic body radiation therapy Conventional conformity index New conformity index |
| 基金项目:福建省医学创新项目（2016-CX-19） |
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| 中文摘要: |
| 目的 对比分析新适形指数（nCI）和常规适形指数（CI）对肺癌立体定向放射治疗（SBRT）计划质量的影响。方法 选取2014至2017年于福建医科大学附属协和医院以SBRT技术治疗的19例周围型肺癌患者（男12例，女7例）进行回顾性研究。每例患者分别设计CI与nCI值相等的两个计划，每个nCI计划处方剂量定义为计划靶区（PTV）48 Gy/4次，且要求95%计划靶区（PTV）达到处方剂量（相同的剂量归一）。采用Wilcoxon秩和检验对剂量学评价指标进行统计学分析。结果 剂量适形图表明，nCI指数不仅能反映靶区外正常组织的剂量，还可以衡量靶区内的剂量分布，且在处方剂量附近nCI指数对计划的质量要求更加严格。CI值和nCI值相等的情况下，两者计划的靶区覆盖率（TC）分别为98.70%和90%，靶区外所有接受处方量105%正常组织的体积与靶区体积的比值（R105%）分别为0.56和0，50%处方剂量线所包含的体积与靶区体积的比值（R50%）分别为5.53和4.99，患侧肺V20分别为15.59%和14.42%，CI计划均大于nCI计划，差异均有统计学意义（Z=-3.823、-3.180、-3.823、-3.783，P<0.05）；靶区外扩2 cm外的最大剂量与靶区内最大剂量的百分比（D2 cm）分别为63.70%和64.07%，差异无统计学意义（P>0.05）。nCI适形指数在D95%与D99%之间其值取得1，符合临床剂量要求，而CI计划不能得出如此结果。结论 nCI适形指数与靶区覆盖率及其他评价指标结合起来评估肺癌SBRT计划较CI指数更具有临床实际意义。 |
| 英文摘要: |
| Objective To analyze the effect of the new conformal index (nCI) and the conventional conformal index (CI) on the treament planning quality of lung stereotopic radiotherapy (SBRT). Methods A total of 19 peripheral lung cancer patients, treated with SBRT in Fujian Medical University Union Hospital from 2014 to 2017, were analyzed retrospectively. Each patient was planned twice yielding identical CI and nCI. The prescription to 95% of planning target volume (PTV) was 48 Gy in four fractions, and renormalization was performed when needed for nineteen nCI plans. The Wilcoxon signed-rank test was used to examine the dosimetric index. Results The dose conformity plots indicate that nCI does not only reflect the dose to the organ at risk outside tumor, but also represents the dose distribution in the PTV. In addition, nCI was stricter with treatment planning qualities when the dose around PTV was closer to the prescribed dose. The value of target coverage (TC), the ratio of out-of-target volumes receiving 105% prescribed dose to the target volume (R105%), the ratio of volume covered by 50% isodose line to the target volume (R50%), and the ipsilateral lung V20 were 98.70%, 0.56, 5.53, 15.59% in the CI plans, vs. 90%, 0, 4.99, 14.42% in the corresponding nCI plans, respectively. All index were significantly lower in the nCI group (Z=-3.823, -3.180, -3.823, -3.783, respectively, P<0.05). The ratio of the maximum dose to the 2 cm external margin from the PTV (D2 cm) to the maximum dose to the PTV were 63.70% and 64.07% respectively in the two groups, and the differences were not statistially significant (P>0.05). The conformity values denoted a clinically favorable value as 1 between D95% and D99% of nCI plans, yet were not applicable to CI plans. Conclusions It is more clinically relavant to evaluate lung SBRT plans using nCI, TC and other indicators collectively than using CI alone. |
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