| 王佳浩,赵鹏军,徐莉霞,赖建军,邓清华,夏冰.上胸段食管癌调强放射治疗中淋巴结意外照射的剂量学研究[J].中华放射医学与防护杂志,2020,40(1):36-41 |
| 上胸段食管癌调强放射治疗中淋巴结意外照射的剂量学研究 |
| Irradiated dose to unprotected lymph node stations in the VMAT and IMRT treatment of patients with upper thoracic esophageal cancer |
| 投稿时间：2019-06-24 |
| DOI：10.3760/cma.j.issn.0254-5098.2020.01.006 |
| 中文关键词: 食管癌 淋巴结意外照射 容积旋转调强放射治疗 静态调强放射治疗 |
| 英文关键词:Esophageal cancer Irradiated dose to unprotected LNS VMAT IMRT |
| 基金项目:浙江省医药卫生科技计划项目（2018KY596） |
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| 中文摘要: |
| 目的 比较上胸段食管癌容积旋转调强放射治疗（VMAT）与5野的静态调强放射治疗（5F-IMRT）在淋巴结意外照射中的剂量学差异，评估两种方式在上胸段食管癌放射治疗中的剂量学特点。方法 选取20例典型的上胸段食管癌患者，在进行靶区勾画时，肿瘤区（GTV）、临床靶区（CTV）不包含所有淋巴结，而将淋巴结单独勾画作为正常组织。对这20例患者分别制定两套计划，即VMAT与5F-IMRT，主要的计划评估参数为靶区的适形指数（CI）、均匀指数（HI），以及接受相应处方剂量水平照射体积百分比V95、V110；危及器官（OAR）评估包括肺的Dmean、V5、V20、V30，心脏的Dmean、V25，脊髓的Dmax，机器调数（MU）。同时评估各个淋巴结的等效均衡剂量（EUD）与接受40 Gy照射剂量的体积百分比V40。结果 5F-IMRT计划在V95%上具有较高的计划靶区（PTV）剂量覆盖率（t=-9.4，P<0.05），VMAT计划的适形指数（CI）优于5F-IMRT（t=-5.3，P<0.05）；5F-IMRT计划较VMAT计划降低平均肺V5 10.9%（t=-7.8，P<0.05），降低平均脊髓Dmax 9%（t=-10.2，P<0.05）；VMAT计划较5F-IMRT计划降低平均MU 18.6%（t=-6.2，P<0.05）；5F-IMRT计划在所有上胸段淋巴结区域的平均EUD值为32.3~61.5 Gy，较VMAT计划（32.5~61.1 Gy）提高4.7%，平均V40提高2.4%。各个上胸段淋巴结区域除左气管支气管淋巴结（106tbL）外的意外照射剂量，与PTV的体积大小充分相关（R=0.716~0.933，P<0.05）。结论 5F-IMRT的放射治疗计划在上胸段食管癌淋巴结意外照射中更具剂量学优势，且肿瘤靶区较大的患者淋巴结区域具有更高的辐射剂量。 |
| 英文摘要: |
| Objective To compare the irradiated dose to unprotected lymph node stations (LNS) between volume-modulated arc therapy (VMAT) and 5-field intensity-modulated radiotherapy (5F-IMRT) in the treatment of patients with upper thoracic esophageal cancer. Methods A total of 20 patients were selected for re-planning. LNS were not included in the GTV and CTV, instead, LNS were contoured as normal tissues. However, LNS were not constrained in the VMAT and 5F-IMRT inverse optimization for protection. Dosimetric parameters of conformal index (CI), homogeneity index (HI) of targets, V95, V110 of planning target volume (PTV), Dmean,V5,V20,V30 of lung, Dmean,V25 of heart, Dmax of spinal cord, MU, as well as the equivalent uniform dose (EUD) and V40 of LNS were compared between the two plans. Results 5F-IMRT was superior in PTV_V95% (t=-9.4, P<0.05), but worse in terms of CI (t=-5.3, P<0.05) compared with VMAT. 5F-IMRT reduced the V5 of lung by 10.9% (t=-7.8, P<0.05) and the Dmax of spinal cord by 9% (t=-10.2, P<0.05), but increased the MU (t=-6.2, P<0.05) compared with VMAT. The average EUD and V40 of LNS in upper thoracic were significantly increased by 4.7% and 2.4% in 5F-IMRT compared with VMAT, respectively. The irradiated doses to LNS were significantly associated with the volume of PTV (R=0.716-0.933, P<0.05) expect for 106tbL. Conclusions The irradiated doses to unprotected LNS were less for IMRT plans and were highly associated with PTV volume in patients with upper thoracic esophageal cancer. |
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