共面和非共面VMAT全脑放疗中保护海马及下丘脑-垂体轴的计划质量  

Plan quality comparison between coplanar and non-coplanar VMAT for the whole brain radiotherapy with hippocampus and hypothalamic-pituitary axis sparing

作　　者：王克强[1] 陈杰[1] 简建波 王鹏[1] 张鑫山 张弘扬 张文学[1] Wang Keqiang;Chen Jie;Jian Jianbo;Wang Peng;Zhang Xinshan;Zhang Hongyang;Zhang Wenxue(Department of Radiation Oncology,Tianjin Medical University General Hospital,Tianjin 300052,China)

机构地区：[1]天津医科大学总医院放射治疗科,天津300052

出　　处：《中华放射肿瘤学杂志》2024年第7期634-641,共8页Chinese Journal of Radiation Oncology

基　　金：吴阶平医学基金(320.6750.17137、320.6750.2020-18-3)。

摘　　要：目的比较共面和非共面容积弧形调强放射治疗(VMAT)技术在全脑放疗中保护海马及下丘脑-垂体(HT-P)轴的计划质量差异。方法回顾性分析2021年11月至2023年8月天津医科大学总医院收治的15例行预防性脑照射的患者,参照RTOG-0933及相关指南勾画海马及HT-P轴,分别设计共面VMAT(co-VMAT)和非共面VMAT(nco-VMAT)计划,处方剂量为30 Gy分10次,利用配对t检验比较两种计划的剂量学指标、计划鲁棒性、计划复杂度及执行效率。结果两种计划均能达到剂量学目标,PTV的D_(2%)、D_(95%)及适形指数(CI)差异没有统计学意义,对于PTV的D^(98%)和均匀性指数(HI),co-VMAT略差于nco-VMAT(D^(98%)为26.37∶26.96 Gy,P=0.001;HI为0.25∶0.24,P=0.002)。co-VMAT中双侧海马的D_(min)为8.55 Gy(左侧)和8.32 Gy(右侧),低于nco-VMAT中的9.31 Gy(左侧)和9.26 Gy(右侧);同时co-VMAT中下丘脑和垂体的D_(mean)低于nco-VMAT计划(下丘脑为11.54∶12.27 Gy,垂体为11.72∶12.1 Gy),差异均有统计学意义(P<0.001)。两种计划中,海马和HT-P轴剂量对误差十分敏感,而PTV和其他危及器官对误差敏感度相对较低。co-VMAT计划比nco-VMAT计划复杂度低,两者在3%/3 mm标准下的γ通过率分别是99.06%±0.60%、98.05%±2.89%。co-VMAT计划的平均出束时间是4.8 min,约为nco-VMAT的2/3,而平均治疗时间为6.3 min,约为nco-VMAT治疗时间的1/2。结论co-VMAT和nco-VMAT均能实现全脑放疗中海马及HT-P轴的保护,co-VMAT计划中靶区的D^(98%)略小,但对海马及HT-P轴的保护更好。两种计划中海马和HT-P轴的剂量都对误差敏感,co-VMAT计划的复杂度更低,执行效率更高,更适合临床治疗。Objective To compare the plan quality between coplanar and non-coplanar volumetric modulated arc therapy(co-VMAT and nco-VMAT)techniques for the whole brain radiotherapy with hippocampus and hypothalamic-pituitary(HT-P)axis sparing.Methods A total of 15 patients who underwent prophylactic cranial irradiation in Tianjin Medical University General Hospital from November 2021 to August 2023 were retrospectively selected.The hippocampus and HT-P axis were delineated according to Radiation Therapy Oncology Group(RTOG)0933 and contouring guidelines for hypothalamus.Co-VMAT and nco-VMAT plans were generated for each patient with a prescription dose of 30 Gy in 10 fractions.Then,dosimetric parameters,plan robustness,plan complexity,and delivery efficiency for both plans were compared using paired t-test.Results Both co-VMAT and nco-VMAT plans could achieve dosimetric objectives.There were no significant differences in D_(2%),D_(95%)and conformity index(CI)of planning target volume(PTV)between the two plans.The D^(98%)and homogeneity index(HI)of PTV in co-VMAT showed a slight inferiority compared to that in nco-VMAT(D^(98%):26.37 Gy vs.26.96 Gy,P=0.001;HI:0.25 vs.0.24,P=0.002).The D_(min)of bilateral hippocampus in co-VMAT were 8.55 Gy(left)and 8.32 Gy(right),which were lower than 9.31 Gy(left)and 9.26 Gy(right)in nco-VMAT.In addition,the D_(mean)of the hypothalamus and pituitary in the co-VMAT plan were lower than those in the nco-VMAT plan(hypothalamus:11.54 Gy vs.12.27 Gy;pituitary:11.72 Gy vs.12.1 Gy,both P<0.001).The doses to the hippocampus and HT-P axis were highly sensitive to errors in both co-VMAT and nco-VMAT plans,while the sensitivity of dose to errors in the PTV and other organs at risk was low.The co-VMAT plan had lower complexity compared to the nco-VMAT plan,withγpassing rate at 3%/3 mm criteria of 99.06%±0.60%and 98.05%±2.89%,respectively.The average beam-on time of the co-VMAT plan was 4.8 min,approximately 2/3 of the time for nco-VMAT,while the average treatment time was 6.3 min,approximately half o

关 键 词：放射疗法 调强适形 容积弧形调强放射治疗 共面 全脑放射疗法 海马及下丘脑-垂体轴 计划鲁棒性 计划复杂度 执行效率 

分 类 号：R817.5[医药卫生—影像医学与核医学]