中华放射医学与防护杂志

胡健,李祥攀,阮长利,昌胜,张爱华,戈伟,徐细明,韩光.左侧乳腺癌患者根治术后靶区分割式计划和常规调强计划的剂量学比较研究[J].中华放射医学与防护杂志,2019,39(11):820-826

左侧乳腺癌患者根治术后靶区分割式计划和常规调强计划的剂量学比较研究

Dosimetric comparison of target-segmented plan versus conventional IMRT plan for post-mastectomy left-sided breast cancer patients

投稿时间：2019-02-09

DOI：10.3760/cma.j.issn.0254-5098.2019.11.004

中文关键词: 乳腺癌根治术靶区分割调强放疗剂量学

英文关键词:Breast cancer Post-mastectomy Target-segmented Intensity modulated radiotherapy Dosimetry

基金项目:

作者	单位	E-mail
胡健	武汉大学人民医院放疗科 430060
李祥攀	武汉大学人民医院放疗科 430060
阮长利	武汉大学人民医院放疗科 430060
昌胜	武汉大学人民医院放疗科 430060
张爱华	武汉大学人民医院放疗科 430060
戈伟	武汉大学人民医院肿瘤科 430060
徐细明	武汉大学人民医院肿瘤科 430060
韩光	湖北省肿瘤医院放疗科, 武汉 430079	hg7913@163.com

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中文摘要:

目的比较左侧乳腺癌患者根治术后靶区分割式放射治疗计划（target segmented plan，TSP）、与TSP优化参数相同但未分割靶区计划（Non-TSP）与常规8野调强计划（8fields IMRT，8F-IMRT）的剂量学差异。方法选择2017年6月至2018年11月于武汉大学人民医院放疗科收治的30例左侧乳腺癌根治术后患者资料，所有胸壁靶区两侧后界连线切肺最大深度均>2 cm。将连线切肺最大深度按照<3 cm、3~4 cm、>4 cm分组。所有患者均采用美国Varian Eclipse治疗计划系统设计3种（TSP、Non-TSP和8F-IMRT）治疗计划，然后对比分析3种方式计划的剂量学参数差异。结果所有患者的治疗计划都达到了处方剂量要求。TSP的D_98%明显低于Non-TSP和8F-IMRT （Z=-3.294，-3.266，P<0.05）；3种计划的均匀指数（HI）和适形指数（CI）比较，差异均无统计学意义（P>0.05）；Non-TSP的加速器治疗的跳数（monitor unit，MU）明显高于TSP和8F-IMRT （Z=-3.04，-2.669，P<0.05）。TSP的D_mean高于8F-IMRT （Z=-3.181，P<0.05）。对于危及器官（Organs at risk，OARs），TSP较Non-TSP和8F-IMRT计划明显降低了所有患者患侧肺和心脏的V_{5 Gy}、V_{10 Gy}、V_{20 Gy}和D_mean（肺：V_{5 Gy}：Z=-3.408、-3.408，V_{10 Gy}：Z=-3.408、-3.408，V_{20 Gy}：Z=-3.408、-3.124，D_mean：Z=-3.408、-3.408，P<0.05；心脏：V_{5 Gy}：Z=-3.408、-3.408，V_{10 Gy}：Z=-3.408、-3.408，V_{20 Gy}：Z=-2.499、-3.067，D_mean：Z=-3.408、-3.408，P<0.05）。Non-TSP健侧乳腺的D_mean明显高于TSP和8F-IMRT （Z=-2.954、-2.215，P<0.05），但D_max的比较差异无统计学意义（P>0.05）。3种计划的脊髓D_max差异无统计学意义（P>0.05）；8F-IMRT肱骨头D_mean明显高于TSP和Non-TSP （Z=-3.01、-2.442，P<0.05）。分组的患侧肺V_{5 Gy}、V_{10 Gy}、V_{20 Gy}和心脏的V_{5 Gy}、V_{10 Gy}、D_mean的Non-TSP和8F-IMRT计划与TSP的幅度差均值均满足D （N-T，A）< D （N-T，B）< D （N-T，C）和D （8F-T，A）< D （8F-T，B）< D （8F-T，C）。结论 TSP能在保持原有靶区剂量充分的同时，在不增加高剂量照射体积的前提下，有效地减小左侧乳腺癌患者根治术后放疗患侧肺和心脏的低剂量区照射体积；随着靶区后界连线切肺最大深度的增加，TSP对患侧肺和心脏的低剂量保护优势愈明显。

英文摘要:

Objective To compare the dosimetric differences among Target-Segmented Plan (TSP), Non-TSP, and conventional static 8-field intensity modulated radiation therapy (8F-IMRT) plan for post-mastectomy irradiation of left-sided breast cancer patients. Methods This study enrolled thirty consecutive breast cancer patients who underwent radical mastectomy and treated with post-op radiation in Department of Radiation Oncology,Renmin Hospital of Wuhan University from June 2017 to November 2018.The clinical target volume (CTV) included the ipsilateral chest wall, supra/infra-clavicular, high-risk partial axillary in high risk, and internal mammary nodes (IMN). The organs at risk (OARs) near the targets, including ipsilateral lung, heart, contralateral breast, ipsilateral humeral head and spinal cord, were contoured as well. The maximum distance of PTV's tangent to the outermost side of the affected lung was more than 2 cm. Depending on the maximum distance,the patients were classified into three groups:A(<3 cm), B(3~4 cm) and C(>4 cm), respectively. Three types of treatment plans (TSP, Non-TSP and 8F-IMRT) were created for each patient using the Eclipse treatment planning system with the same dose optimization objective. The dose-volume histograms were compared for the PTVs and OARs. Results All plans achieved the intended dose criteria.The D_98%of TSP was lower than that of Non-TSP and 8F-IMRT (Z=-3.294,-3.266, P<0.05). However, the homogeneity index (HI) and conformal index (CI) of the three plans had no statistically significant difference among the three plans (P>0.05).Non-TSP required more Monitor Units (MUs)than the other two plans (Z=-3.04,-2.669, P<0.05). The D_mean of TSP was higher than that of 8F-IMRT (Z=-3.181, P<0.05). Compared with Non-TSP and 8F-IMRT plans,TSP significantly reduced V_{5 Gy}, V_{10 Gy}, V_{20 Gy} and D_meanof ipsilateral lung and heart in all patients (lung:V_{5 Gy}:Z=-3.408,-3.408;V_{10 Gy}:Z=-3.408,-3.408;V_{20 Gy}:Z=-3.408,-3.124;D_mean:Z=-3.408,-3.408,P<0.05;heart:V_{5 Gy}:Z=-3.408,-3.408;V_{10 Gy}:Z=-3.408,-3.408;V_{20 Gy}:Z=-2.499,-3.067;D_mean:Z=-3.408,-3.408,P<0.05). The D_meanof contralateral breast in Non-TSP was higher than that in TSP and 8F-IMRT (Z=-2.954, -2.215, P<0.05),and the D_maxhas no significant difference in (P>0.05). There was no significant difference in spinal cord D_max among the three plans, but the D_mean of humeral head in 8F-IMRT was higher than that in TSP and Non-TSP (Z=-3.01,-2.442,P<0.05).In the three groups, the mean amplitude of difference comparing Non-TSP and 8F-IMRT with TSP in ipsilateral lung(V_{5 Gy},V_{10 Gy},V_{20 Gy}) and heart(V_{5 Gy},V_{10 Gy},D_mean) satisfied the relation:D(N-T,A)<D(N-T,B) <D(N-T,C)和D(8F-T,A)<D(8F-T,B) <D(8F-T,C). Conclusions For post-mastectomy left-sided breast cancer patients,TSP is not only dosimetrically feasible as Non-TSP and 8F-IMRT treatment techniques, but also could effectively reduce the irradiation volume of the ipsilateral lung and heart in the low dose area with minimum adverse dosimetric impact on the treatment targets and other OARs.The advantage of TSP is more prominent with increasing curvature of the clinic target volume.

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