Four-dimensional Monte Carlo dose calculation

描述(申请人提供)：质子疗法目前正在兴起，因此被认为是治疗肺癌患者的方法。目前，大多数质子治疗患者正在接受被动散射质子治疗。由于较新的设备只设计用于铅笔束扫描，而现有的设备正在升级为束流扫描，可以预期，束流扫描将是未来的选择方法。运动的剂量学效应在质子治疗中可能比在传统治疗中更严重，因为远端剂量急剧下降。此外，质子束扫描会引起铅笔束运动和目标运动之间的相互作用。在电子束扫描可以用于临床肺部治疗之前，我们必须了解在使用时间依赖的递送系统治疗移动目标时的剂量学效应。在光束扫描建立之前，这项研究现在就需要完成！因此，我们提出用四维蒙特卡罗方法研究质子束扫描处理运动目标时铅笔束运动和目标运动之间的潜在相互作用效应。我们预计，根据运动参数和射束传输参数，可能存在肿瘤剂量不足或危险器官剂量变化超过30%的情况。因此，对于某些输送和运动参数，可能不使用质子束扫描(即使在门控输送的情况下)，而不使用标准的被动散射质子束疗法。相互作用效应的影响可以受到不同的束流传输参数的影响，例如铅笔束斑大小、重涂策略等。我们还建议研究高局部剂量率的扫描束传输的生物影响。 公共卫生相关性：质子疗法目前正在上升，因此被认为是治疗肺癌的方法。然而，质子束扫描会引起铅笔束运动和目标运动之间的相互作用。在电子束扫描可以用于临床肺部治疗之前，我们必须了解在使用时间依赖的递送系统治疗移动目标时的剂量学效应。这项研究需要现在就完成，在光束扫描成为临床应用之前！因此，我们提出用四维蒙特卡罗方法研究质子束扫描处理运动目标时铅笔束运动和目标运动之间的潜在相互作用效应。

DESCRIPTION (provided by applicant): 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. PUBLIC HEALTH RELEVANCE: Proton therapy is currently on the rise and is thus considered for treating lung cancer. However, 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 clinically 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.