Mid-range probing-towards range-guided particle therapy.
Mid-range probing-towards range-guided particle therapy.
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DOI：
10.1088/1361-6560/aaca1b
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发表时间：
2018-06-27
影响因子：
3.5
通讯作者：
Lu W
中科院分区：
文献类型：
--
作者：
Chen M;Zhong Y;Shao Y;Jiang S;Lu W
粒子治疗可以达到很好的剂量定位，但对范围不确定性很敏感。因此，治疗前的在线体内范围验证对于治疗安全和质量保证至关重要。我们介绍了一种新的距离探测技术，该技术使用从治疗计划中选择的中距离治疗点作为探测光束，在铅笔束扫描的其他治疗点之前传递。利用束内正电子发射层析成像（PET）扫描仪获取探测光斑信号，并将重建的光斑位置与预先计算的位置进行比较，以测量距离位移。中程探测确保布拉格峰保持在肿瘤内部，即使与计划有显著的范围变化。单层斑点比多层斑点更容易检测，而不需要跨层斑点涂抹。在治疗剂量下，探测光束比低剂量成像光束提供更高的正电子活动和范围可探测性，最高可达两个数量级，而不会使患者暴露于额外的辐射。较高的正电子活性允许在较短的采集时间内进行充分的信号统计，因此减少了正电子发射器的代谢冲洗。因此，距离从计划可以很容易地测量。本文还介绍了两种在线距离补偿方案修改方法。如果范围位移超过一定的容差，我们就进行校正。我们使用模拟粒子治疗方案和在线解剖改变来研究可行性。为了说明，我们演示了使用模拟探测剂量的范围位移测量。所提出的距离探测和校正方法有效地处理了模拟情况下的距离偏移。范围补偿适应和优化都考虑到在线变化，以便交付剂量与计划剂量相匹配。随着专用的在线束内PET扫描仪以及目前正在开发的幻影和临床研究，这种新策略可能会开辟一种范围引导粒子治疗（RGPT1）范式。
Particle therapy can achieve excellent dose localization but is sensitive to range uncertainty. Therefore, online in-vivo range verification before treatment is critical for treatment safety and quality assurance. We introduce a novel range-probing technique that uses mid-range treatment spots selected from the treatment plan as probing beams to be delivered before other treatment spots in pencil beam scanning. The probing spot signal can be acquired by an in-beam positron emission tomography (PET) scanner, and the reconstructed spot positions are compared with pre-calculated positions to measure the range shift. Mid-range probing ensures that the Bragg peaks stay inside the tumor even with significant range variation from the plan. Single-layered spots enable easier spot detection than multi-layered spots without cross-layered spot smearing. With therapeutic dose, the probing beam offers higher positron activities and range detectability than the low-dose imaging beam by up to two orders of magnitude, without exposing patients to extra radiation. Higher positron activities allow sufficient signal statistics in shorter acquisition time, therefore reducing metabolic washout of positron emitters. Thus, range shifts from the plan can be measured easily. We also describe two online range-compensated plan modification methods. We apply correction, if the range shift is above a certain tolerance. We studied feasibility using simulated particle treatment plans with online anatomical changes. For illustration, we demonstrate range shift measurement using simulated probing dose. The proposed range probing and correction effectively handled range shifts in the simulated cases. Both range-compensated adaptation and optimization accounted for online changes so that the delivered dose matched the planned dose. With a dedicated online in-beam PET scanner and phantom and clinical studies, which are currently being developed, this novel strategy may open up a range-guided particle therapy (RGPT1) paradigm.
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影响因子：
3.5
作者：
Attanasi, F.;Belcari, N.;Vecchio, S.
通讯作者：
Vecchio, S.
影响因子：
3.5
作者：
Dendooven, P.;Buitenhuis, H. J. T.;Brandenburg, S.
通讯作者：
Brandenburg, S.
影响因子：
3.5
作者：
Mumot, M.;Algranati, C.;Lomax, A. J.
通讯作者：
Lomax, A. J.
影响因子：
3.5
作者：
Zhang, M.;Westerly, D. C.;Mackie, T. R.
通讯作者：
Mackie, T. R.
影响因子：
3.8
作者：
SCHNEIDER, U;PEDRONI, E
通讯作者：
PEDRONI, E