Dosimetric evaluation of four whole brain radiation therapy approaches with hippocampus and inner ear avoidance and simultaneous integrated boost for limited brain metastases
Dosimetric evaluation of four whole brain radiation therapy approaches with hippocampus and inner ear avoidance and simultaneous integrated boost for limited brain metastases
复制标题
对四种全脑放射治疗方法的剂量学评估，其中包括海马和内耳回避以及有限脑转移的同步综合增强
DOI：
10.1186/s13014-019-1255-7
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发表时间：
2019-03-15
影响因子：
3.6
通讯作者：
Yuan, Shuanghu
中科院分区：
文献类型：
--
作者：
Jiang, Aijun;Sun, Weipeng;Yuan, Shuanghu
目的对四种不同的海马体和内耳回避同时综合增强全脑放疗方式治疗局限性脑转移瘤进行剂量学评价。方法利用10例有限（1-5）脑转移患者的计算机断层扫描/磁共振成像资料，重新规划步进-射调强放疗（sIMRT）、动态调强放疗（dIMRT）、体积调制弧线治疗（VMAT）和螺旋断层治疗（Tomo）。将40-50 Gy（10份）和30 Gy（10份）的处方剂量分别同时递送至转移灶和全脑体积。海马剂量符合RTOG 0933海马回避标准（Dmax≤17 Gy, D100%≤10 Gy）。内耳剂量控制在Dmean≤15 Gy。比较靶覆盖率（TC）、均匀性指数（HI）、一致性指数（CI）、最大剂量（Dmax）、最小剂量（Dmin）和危及器官剂量（OARs）。结果所有方案均符合规定的剂量限制。计划转移靶体积（PTVmets）覆盖率的平均百分比从97.1到99.4%不等。在规划脑靶体积（PTVbrain）方面，Tomo的平均D2%（37.5±2.8 Gy）最低，平均D98%（25.2±2.0 Gy）最高，TC（92.6%±2.1%）和CI（0.79±0.06）最佳。两种固定龙门IMRT方式（步进和射击，动态）提供了相似的ptv脑剂量均匀性（均为0.76）。对海马的最大和最小剂量以及对眼睛、晶状体和视神经的最大剂量在四种方法中观察到显著差异。结论四种放疗方式均能有效避免海马和内耳损伤。Tomo获得了满意的ptv脑覆盖和最佳的均匀性指数。临床试验注册：clinicaltrials .gov, NCT03414944。2018年1月29日注册
AimsTo perform a dosimetric evaluation of four different simultaneous integrated boost whole brain radiotherapy modalities with hippocampus and inner ear avoidance in the treatment of limited brain metastases.MethodsComputed tomography/magnetic resonance imaging data of 10 patients with limited (1–5) brain metastases were used to replan step-and-shoot intensity-modulated radiotherapy (sIMRT), dynamic intensity-modulated radiation therapy (dIMRT), volumetric-modulated arc therapy (VMAT), and helical tomotherapy (Tomo). The prescribed doses of 40–50 Gy in 10 fractions and 30 Gy in 10 fractions were simultaneously delivered to the metastatic lesions and the whole-brain volume, respectively. The hippocampal dose met the RTOG 0933 criteria for hippocampal avoidance (Dmax ≤17 Gy, D100% ≤10 Gy). The inner ear dose was restrained to Dmean ≤15 Gy. Target coverage (TC), homogeneity index (HI), conformity index (CI), maximum dose (Dmax), minimum dose (Dmin) and dose to organs at risk (OARs) were compared.ResultsAll plans met the indicated dose restrictions. The mean percentage of planning target volume of metastases (PTVmets) coverage ranged from 97.1 to 99.4%. For planning target volume of brain (PTVbrain), Tomo provided the lowest average D2% (37.5 ± 2.8 Gy), the highest average D98% (25.2 ± 2.0 Gy), and the best TC (92.6% ± 2.1%) and CI (0.79 ± 0.06). The two fixed gantry IMRT modalities (step and shot, dynamic) provided similar PTVbrain dose homogeneity (both 0.76). Significant differences across the four approaches were observed for the maximum and minimum doses to the hippocampus and the maximum doses to the eyes, lens and optic nerves.ConclusionAll four radiotherapy modalities produced acceptable treatment plans with good avoidance of the hippocampus and inner ear. Tomo obtained satisfactory PTVbrain coverage and the best homogeneity index.Trial registrationClinicaltrials.gov, NCT03414944 . Registered 29 January 2018