Four-dimensional Monte Carlo dose calculation

质子治疗目前正在兴起，因此被认为是治疗肺癌患者。 大多数质子治疗患者目前正在接受被动散射质子治疗 疗法由于新的设施正在设计用于笔形波束扫描， 设施正在向波束扫描升级，可以预期，波束扫描将是 未来的选择方法。 运动的剂量效应在质子治疗中可能比在常规治疗中更严重。 由于远端剂量急剧下降，此外，质子束扫描可以导致 笔形波束运动和目标运动之间的相互作用效应。在光束扫描之前， 在临床上用于肺部治疗时，我们必须了解剂量学效应， 用时间依赖的输送系统治疗移动目标。这项研究现在就需要完成， 在光束扫描建立之前！ 因此，我们建议应用四维蒙特卡罗来研究潜在的相互作用 质子治疗运动目标时笔形束流运动与目标运动的关系 波束扫描我们预计，可能会有肿瘤剂量不足或剂量变化， 取决于运动参数和射束输送参数，处于风险中的器官超过30%。 因此，对于某些递送和运动参数，可以不使用质子束扫描（不使用 即使使用门控输送）而不是标准的被动散射质子束治疗。的影响 相互作用效应的影响可以通过改变射束传输参数来影响，例如笔形射束光斑 我们还建议研究扫描光束的生物学影响 局部剂量率高。

Proton therapy is currently on the rise and is thus considered for treating lung cancer patients. The majority of proton therapy patients are currently being treated with passive scattered proton therapy. As newer facilities are being designed for pencil beam scanning only and existing facilities are upgrading towards beam scanning, it can be expected that beam scanning will be the method of choice in the future. Dosimetric effects of motion are potentially more severe in proton therapy than in conventional therapy due to the sharp distal dose fall-off. Furthermore, proton beam scanning can cause interplay effects between pencil beam motion and target motion. Before beam scanning can be used clinically for lung treatments it is mandatory that we understand dosimetric effects when treating moving targets with a time-dependent delivery system. This study needs to be done now, before beam scanning becomes established! Consequently, we propose to apply four-dimensional Monte Carlo to study potential interplay effects between pencil beam motion and target motion when treating moving targets with proton beam scanning. We expect that there could be under-dosage of the tumor or dose changes in organs at risk in excess of 30% depending on motion parameters and beam delivery parameters. Thus, for certain delivery and motion parameters, proton beam scanning might not be used (not even with gated delivery) instead of standard passive scattered proton beam therapy. The impact of interplay effects can be influenced by varying beam delivery parameters, e.g. pencil beam spot size, re-painting strategy, etc. We also propose to study the biological impact of scanned beam delivery with high local dose rate.