Toward improved target conformity for two spot scanning proton therapy delivery systems using dynamic collimation
Toward improved target conformity for two spot scanning proton therapy delivery systems using dynamic collimation
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DOI：
10.1118/1.4942375
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发表时间：
2016-03-01
期刊：
影响因子：
3.8
通讯作者：
Hyer, Daniel E.
中科院分区：
文献类型：
--
作者：
Moignier, Alexandra;Gelover, Edgar;Hyer, Daniel E.
目的：旨在量化使用动态准直系统（DCS）和两个点扫描质子治疗输送系统在脑和头颈部肿瘤治疗中靶点符合性的改善（通用喷嘴，UN，和专用喷嘴，DN），在100至230 MeV的能量范围内具有5.2和3.2 mm的中值光斑尺寸。在我们的内部治疗计划系统中，使用UN和DN射束模型计算了未准直和准直计划，用于之前接受过点扫描质子治疗的患者的5个脑部和10个头颈部数据集。UN和DN计划均使用来自临床计划的处方剂量和射束角度。针对UN和DN计算了未准直和准直计划之间靶周围10 mm环的平均剂量的平均减少。结果：UN和DN计划的10 mm环平均剂量平均减少13.7%，而DN计划的10 mm环平均剂量平均减少13.7%（95% CI：11.6%-15.7%; p < 0.0001）和11.5%（95% CI：9.5%-13.5%; p < 0.0001），7.1%（95% CI：4.4%-9.8%; p < 0.001）和6.3%（95% CI：3.7%-9.0%; p < 0.001）。准直UN计划与未准直DN计划相比更适形（所有脑部病例和60%的头颈部病例）或等同（40%的头颈部病例）。准直DN计划提供了最高的conformity.Conclusions：DCS添加到UN或DN提高了目标符合性。DCS可能是特别感兴趣的网站与联合国系统寻找一个更经济的解决方案，而不是升级喷嘴，以改善其点扫描质子治疗系统的目标一致性。(C)2016年美国医学物理学家协会。
Purpose: To quantify improvement in target conformity in brain and head and neck tumor treatments resulting from the use of a dynamic collimation system (DCS) with two spot scanning proton therapy delivery systems (universal nozzle, UN, and dedicated nozzle, DN) with median spot sizes of 5.2 and 3.2 mm over a range of energies from 100 to 230 MeV.Methods: Uncollimated and collimated plans were calculated with both UN and DN beam models implemented within our in-house treatment planning system for five brain and ten head and neck datasets in patients previously treated with spot scanning proton therapy. The prescription dose and beam angles from the clinical plans were used for both the UN and DN plans. The average reduction of the mean dose to the 10-mm ring surrounding the target between the uncollimated and collimated plans was calculated for the UN and the DN. Target conformity was analyzed using the mean dose to 1-mm thickness rings surrounding the target at increasing distances ranging from 1 to 10 mm.Results: The average reductions of the 10-mm ring mean dose for the UN and DN plans were 13.7% (95% CI: 11.6%-15.7%; p < 0.0001) and 11.5% (95% CI: 9.5%-13.5%; p < 0.0001) across all brain cases and 7.1% (95% CI: 4.4%-9.8%; p < 0.001) and 6.3% (95% CI: 3.7%-9.0%; p < 0.001), respectively, across all head and neck cases. The collimated UN plans were either more conformal (all brain cases and 60% of the head and neck cases) than or equivalent (40% of the head and neck cases) to the uncollimated DN plans. The collimated DN plans offered the highest conformity.Conclusions: The DCS added either to the UN or DN improved the target conformity. The DCS may be of particular interest for sites with UN systems looking for a more economical solution than upgrading the nozzle to improve the target conformity of their spot scanning proton therapy system. (C) 2016 American Association of Physicists in Medicine.