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| 不同放疗技术实施多发脑转移瘤立体定向放疗的剂量学研究 |
| Dosimetric Study of Stereotactic Radiotherapy for Multiple Brain Metastases Using Different Techniques |
| 投稿时间：2024-12-19 修订日期：2025-02-05 |
| DOI： |
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| 中文关键词: 多发脑转移瘤 立体定向放射治疗 HyperArc 螺旋断层放射治疗 |
| 英文关键词:Multiple brain metastases Stereotactic radiotherapy HyperArc Helical tomotherapy |
| 基金项目:上海市卫生健康委员会卫生行业临床研究专项(20224Y0025) |
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| 中文摘要: |
| [目的]分析不同放疗技术在多发脑转移瘤立体定向放射治疗（Stereotactic Radiotherapy, SRT）中的剂量学差异。[方法]回顾性分析10例多发脑转移瘤病例，处方剂量35Gy/5Fx，分别生成三种技术共四组计划：VMAT(volumetric modulated arc therapy)，HA(HyperArc), HT-1(helical tomotherapy, 1cm field width),HT-2.5(helical tomotherapy, 2.5cm field width)，比较四组计划的剂量学参数和出束时间。探究靶区体积和靶区间距对各技术间脑剂量学参数差异的影响。[结果]VMAT和HA的适形性指数(conformal index, CI)无统计学差异（P=0.980），均高于HT组（P=0.021；P=0.005；P=0.011；P=0.005）。均匀性指数(homogeneity index, HI)无统计学差异（P=0.804），均低于HT组（P=0.040；P=0.004；P=0.048；P=0.010）。HA的剂量梯度跌落指数(gradient index, GI)最优，其次依次为VMAT、HT-1和HT-2.5。HA计划的脑平均剂量为四组中最低（P=0.037；P=0.016；P<0.001）。对于脑剂量体积V5Gy，V8Gy，V10Gy，V12Gy，V15Gy，V20Gy，V25Gy，V30Gy，HA和HT-1的V5Gy近似（P=0.069），优于VMAT和HT-2.5（P=0.013；P<0.001；P=0.022；P<0.001,）。HA在V8Gy~V30Gy均为最低，VMAT从V15Gy开始优于HT-1，HT-2.5在所有剂量段脑受照体积最高。靶区间距对各技术间的差异影响不大。随靶区体积增加，HA与VMAT在V5Gy、V8Gy上的差异减小，VMAT相对HT-1在V15Gy以上的优势减弱，HT-1与HT-2.5在V5Gy、V8Gy和V25Gy的差异减小。HA，VMAT，HT-2.5，HT-1出束时间依次增加。[结论]对于多发脑转移瘤SRT，HA技术相比VMAT和HT技术在适形性、均匀性、剂量梯度跌落，对脑的保护和治疗效率方面均表现更好。VMAT技术与HT-1技术在放射性脑坏死相关风险因素上表现近似，但前者治疗时间大幅缩短。 |
| 英文摘要: |
| [Objective]To analyze the dosimetric differences among various treatment techniques in stereotactic radiotherapy (SRT) for multiple brain metastases.[Methods]A retrospective analysis was conducted on 10 cases of multiple brain metastases, with a prescribed dose regimen of 35 Gy delivered in five fractions. Four different plans were generated using three techniques: volumetric modulated arc therapy (VMAT), HyperArc (HA), and helical tomotherapy with field widths of 1 cm (HT-1) and 2.5 cm (HT-2.5). Dosimetric parameters and beam-on time were compared across these four plans. Additionally, the study explored how target volume and inter-target distance affect the differences in brain-related dosimetric parameters between the various techniques.[Results]There was no statistically significant difference in the conformal index (CI) between VMAT and HA (P=0.980), both of which were better than the HT groups (P=0.021；P=0.005；P=0.011；P=0.005). There was also no significant difference in the homogeneity index (HI) between VMAT and HA(P=0.804), both of which were lower compared to the HT groups (P=0.040；P=0.004；P=0.048；P=0.010). The gradient index (GI) was optimal for the HA plan, followed by VMAT, HT-1, and HT-2.5. The mean brain dose in HA plan was the lowest among the four plans (P=0.037, P=0.016, P<0.001).Regarding the dose volumes V5Gy，V8Gy，V10Gy，V12Gy，V15Gy，V20Gy，V25Gy，V30Gy of brain, HA and HT-1 showed similar V5Gy values (P=0.069), both superior to VMAT and HT-2.5 (P=0.013, P<0.001, P=0.022, P<0.001). HA had the lowest values from V8Gy to V30Gy. VMAT demonstrated advantages over HT-1 starting from V15Gy. HT-2.5 had the highest irradiated brain volume across all dose levels. The distance between targets has no impact on the differences among various radiotherapy techniques.As target volume increased, the differences between HA and VMAT at V5Gy and V8Gy decreased.The advantage of VMAT over HT-1 decreased for doses above 15 Gy .Differences between HT-1 and HT-2.5 reduced at V5Gy, V8Gy, and V25Gy. Beam-on times increased in the sequence of HA, VMAT, HT-2.5, and HT-1.[Conclusion]For SRT treatment of multiple brain metastases，the HA technique outperformed VMAT and HT techniques in conformity, homogeneity, dose gradient fall-off, brain protection, and treatment efficiency. VMAT and HT-1 exhibit comparable factors related to brain necrosis，but the former significantly reduces treatment time. |
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