Use of a LYSO-based Compton camera for prompt gamma range verification in proton therapy
Use of a LYSO-based Compton camera for prompt gamma range verification in proton therapy
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DOI：
10.1002/mp.12626
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发表时间：
2017-12-01
期刊：
影响因子：
3.8
通讯作者：
Huang, Hsuan-Ming
中科院分区：
文献类型：
--
作者：
Jan, Meei-Ling;Hsiao, Ing-Tsung;Huang, Hsuan-Ming
目的：康普顿照相机（CC），测量质子治疗过程中发射的瞬发伽马（PG），是一种潜在的有用的成像设备，用于质子范围验证。本研究的目的是评估如何以及重建PG图像从各种两阶段CC配置再现远端衰减的PG emission.Methods：我们进行了Monte Carlo模拟，以评估不同的两阶段CC定位正交的质子笔形束照射水幻影。结果进行了比较，获得了一个三级CC。结果：我们发现：（a）探测器的位置分辨率比探测器的能量分辨率在预测最大发射深度和远端衰减位置时导致更大的不确定性;（B）减少吸收体探测器的厚度可以减少位置分辨率对重建图像质量的影响并改善衰减位置估计数;（c）不完全吸收的PG可以通过限制入射伽马能量已知PG能谱峰过滤;和（d）有更大的偏差和更少的准确性预测远端衰减位置与三阶段CC相比，两阶段CC。结论：本研究表明，使用各种CC设计和事件选择方法，以提高成像的PG射线的可行性。在我们设计的两级CC中，基于LYSO的薄吸收体可以提供比厚吸收体更好的远端衰减位置预测。与三级CC相比，两级CC偏差更小，并且提供更准确的范围验证。(C)2017年美国医学物理学家协会
Purpose: A Compton camera (CC), which measures prompt gammas (PGs) emitted during proton therapy, is a potentially useful imaging device for proton range verification. The aim of this study was to evaluate how well the reconstructed PG images obtained from various two-stage CC configurations reproduce the distal falloff of the PG emission.Methods: We conducted Monte Carlo simulations to evaluate different two-stage CCs positioned orthogonal to a proton pencil beam irradiating a water phantom. The results were compared with those obtained for a three-stage CC. In particular, all detectors were made of lutetium-yttrium orthosilicate (LYSO) crystals.Results: We found that: (a) the position resolution of the detector led to more uncertainty in predicting the depth of maximum emission and distal falloff positions than did the energy resolution of the detector; (b) reducing the thickness of the absorber detector reduces the effect of position resolution on the quality of reconstructed images and improves falloff position estimates; (c) incomplete absorption of PGs can be filtered by restricting incident gamma energies to known PG energy spectral peaks; and (d) there is greater bias and less accuracy in predicting distal falloff positions with the three-stage CC compared with the two-stage CC.Conclusions: This study demonstrates the feasibility of using various CC designs and event selection methods to improve the imaging of PG rays. In our designed two-stage CCs, the thin LYSO-based absorber can provide better predictions of the distal falloff positions than the thick one. Compared to three-stage CCs, two-stage CCs are less biased and provide more accurate range verification. (C) 2017 American Association of Physicists in Medicine