早期鼻咽癌调强放疗设置颈前后部限量环减少头颈淋巴水肿的剂量学研究  

Reduction of head and neck lymphedema by placing dose limiting rings in the anterior and posterior regions of the neck for treating early nasopharyngeal carcinoma using intensity-modulated radiotherapy:A dosimetric perspective

作　　者：廖恺 田允鸿 郑荣辉 何彩娴 彭继勇 李慧君 LIAO Kai;TIAN Yunhong;ZHENG Ronghui;HE Caixian;PENG Jiyong;LI Huijun(Department of Radiotherapy,Cancer Hospital,Guangzhou Medical University,Guangzhou 510095,China;不详)

机构地区：[1]广州医科大学附属肿瘤医院放疗科,广州510095

出　　处：《实用医学杂志》2024年第12期1659-1664,共6页The Journal of Practical Medicine

基　　金：广东省自然科学基金面上项目(编号:2023A1515011670);广州市卫生健康科技一般引导项目(编号:20221A011097)。

摘　　要：目的从剂量学角度探讨早期鼻咽癌调强放疗模式下为减少头颈淋巴水肿设置颈前后部限量环的最佳限制剂量。方法纳入2022年1-9月在广州医科大学附属肿瘤医院行放疗CT定位的初治早期鼻咽癌患者15例,每个病例设计5套放疗计划。计划A为常规无限量环计划,计划B-E为设置限量环计划,分别设置20、18、16、14 Gy等剂量限制梯度,其余参数与计划A保持一致。通过随机区组设计资料的方差分析和两两比较,评估对靶区覆盖及危及器官限量的影响,确定最佳剂量限值。结果最终确定16 Gy为取得靶区覆盖及危及器官限量平衡的最佳剂量限值截点。颈前后部设置16 Gy限量环,与常规计划相比,基本不影响靶区剂量覆盖(P>0.05),仅稍影响均匀性(P<0.05);不影响内耳、下颌骨、脑干的剂量(均P>0.05);可以显著降低口腔、喉、甲状腺剂量(均P<0.05);稍增加腮腺、脊髓剂量(均P<0.05),但仍在耐受量范围内。结论通过剂量学研究,确定了颈前后部限量环的最佳剂量限值,以期为临床提供一种减少早期鼻咽癌放疗后头颈淋巴水肿的调强放疗计划设计方式。Objective To establish an optimal limiting dose for dose limiting rings placed in the anterior and posterior regions of the neck for reducing head and neck lymphedema under intensity-modulated radiation therapy(IMRT)for early nasopharyngeal carcinoma(NPC)from a dosimetric perspective.Method Fifteen newly diagnosed early-stage nasopharyngeal carcinoma patients who underwent CT localization for radiotherapy at the Cancer Hospital of Guangzhou Medical University from January to September 2022 were included in the study.Each case was designed with five sets of radiotherapy plans.Plan A consisted of conventional unlimited-field plans,while Plans B-E consisted of limited-field plans with dose constraints set at 20,18,16,and 14 Gy,respectively,with the remaining parameters consistent with Plan A.The impact on target coverage and organ-at-risk constraints was evaluated through variance analysis and pairwise multiple comparisons using a randomized block design to determine the optimal dose limits.Results The gradient of 16Gy was determined as the optimal dose limiting cutoff point for achieving the balance between target coverage and organ limiting dose.Compared with the conventional plan,The plans with the placement of a cervical anterior and posterior dose limiting ring(16Gy)did not change the target dose coverage(P>0.05),but only yielded a slight change in the homogeneity index(P<0.05).It did not cause any changes of the dosage in the inner ear,mandible,and brainstem(all P>0.05),but lead to statistically significant reductions in the oral cavity,throat,and thyroid(all P<0.05).It caused a slight increase of the dose in the parotid gland and spinal cord(both P<0.05),but the increased dose was anyhow within the tolerance range.Conclusion The dosimetric investigation determines an optimal dose limit cutoff point for the cervical anterior and posterior dose limiting rings.It is expected to provide a design method for IMRT plans to reduce head and neck lymphedema after radiotherapy for early NPC.

关 键 词：鼻咽癌 适形调强放疗 淋巴水肿 剂量学 

分 类 号：R739.63[医药卫生—肿瘤]