Reconstruction for proton computed tomography by tracing proton trajectories: A Monte Carlo study
Reconstruction for proton computed tomography by tracing proton trajectories: A Monte Carlo study
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DOI：
10.1118/1.2171507
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发表时间：
2006-03-01
期刊：
影响因子：
3.8
通讯作者：
Schulte, RW
中科院分区：
文献类型：
--
作者：
Li, TF;Liang, ZR;Schulte, RW
质子计算机断层扫描（pCT）由于其独特的成像特性，低辐射剂量，以及其可能用于治疗计划和在线靶定位质子治疗在过去的几十年中一直在探索。然而，pCT图像的重建是具有挑战性的，因为要成像的对象内的质子路径在统计上受到多重库仑散射的影响。在本文中，我们采用基于GEANT 4的Monte Carlo模拟的二维pCT重建的椭圆体模的研究可能使用的代数重建技术（ART）与三种不同的路径估计方法的pCT重建。第一种方法假设一个直线路径（SLP）连接的质子入口和出口的位置，第二种方法适应最可能的路径（MLP）理论上确定的均匀介质，和第三种方法采用三次样条路径（CSP）。ART重建显示，当从SLP [2线对（lp）cm（-1）]到弯曲CSP和MLP路径估计（5 lp cm（-1））时，空间分辨率逐渐提高。基于MLP的ART算法具有最快的收敛速度和最小的残差的所有三个估计。这项工作证明了跟踪弯曲质子路径的优势，结合ART算法和弯曲路径估计。(c)2006年美国医学物理学家协会。
Proton computed tomography (pCT) has been explored in the past decades because of its unique imaging characteristics, low radiation dose, and its possible use for treatment planning and on-line target localization in proton therapy. However, reconstruction of pCT images is challenging because the proton path within the object to be imaged is statistically affected by multiple Coulomb scattering. In this paper, we employ GEANT4-based Monte Carlo simulations of the two-dimensional pCT reconstruction of an elliptical phantom to investigate the possible use of the algebraic reconstruction technique (ART) with three different path-estimation methods for pCT reconstruction. The first method assumes a straight-line path (SLP) connecting the proton entry and exit positions, the second method adapts the most-likely path (MLP) theoretically determined for a uniform medium, and the third method employs a cubic spline path (CSP). The ART reconstructions showed progressive improvement of spatial resolution when going from the SLP [2 line pairs (lp) cm(-1)] to the curved CSP and MLP path estimates (5 lp cm(-1)). The MLP-based ART algorithm had the fastest convergence and smallest residual error of all three estimates. This work demonstrates the advantage of tracking curved proton paths in conjunction with the ART algorithm and curved path estimates. (c) 2006 American Association of Physicists in Medicine.