Taherparvar Payvand, Sadremomtaz Alireza
Department of Physics, Faculty of Science, University of Guilan, Namjoo Avenue, P.O. Box 41635-1914, Rasht, Gilan, 4193833697, Iran.
Australas Phys Eng Sci Med. 2018 Mar;41(1):31-39. doi: 10.1007/s13246-017-0607-6. Epub 2017 Dec 11.
GATE is currently considered in scintigraphic imaging as a powerful tool to develop, design and optimize nuclear medicine modalities. This paper describes the GATE simulation of a pixelated gamma camera which is dedicated to high resolution of small animals imaging. It consists of a CsI(Na) crystal array coupled to position sensitive photomultiplier tube. The simulation model includes photon tracking through low energy high resolution hexagonal parallel holes collimator, CsI(Na) pixelated crystal, back-compartment, and camera shielding. Simulations were compared with experimental results by some criteria such as energy spectrum, energy resolution, spatial resolution, sensitivity and count profiles obtained from line and point sources imaging. The acquired energy resolution show good agreement with measured spectra. Difference between calculated and experimental values is about 0.3% for absolute sensitivity measurement. The result of the image uniformity is more consistent after implementation of non-uniformity correction. These values were about 1.3 and 1.2% for experimental and simulation study in the central field of view, respectively. Measurements showed that the spatial resolutions differences at the head surface along the long dimensions of gamma camera for simulation and experimental differed by no more than 4%.Differences along the short axis were about 6%. The FWHMs of images of point and line sources show good consistency between experimental images and corresponding simulated ones. The difference between experimental and simulated system parameters was within 11%. Our results demonstrate the ability and flexibility of the Monte Carlo simulation for modeling pixelated gamma camera with position sensitive detector by selecting the appropriate parameters for digitizer chain and collimator position on the detector surface.
在闪烁成像中，GATE目前被视为开发、设计和优化核医学模态的强大工具。本文描述了用于小动物高分辨率成像的像素化伽马相机的GATE模拟。它由耦合到位置灵敏光电倍增管的CsI(Na)晶体阵列组成。模拟模型包括光子通过低能高分辨率六边形平行孔准直器、CsI(Na)像素化晶体、后舱和相机屏蔽的跟踪。通过能量谱、能量分辨率、空间分辨率、灵敏度以及从线源和点源成像获得的计数剖面等标准，将模拟结果与实验结果进行了比较。所获得的能量分辨率与测量光谱显示出良好的一致性。绝对灵敏度测量的计算值与实验值之间的差异约为0.3%。实施不均匀性校正后，图像均匀性的结果更加一致。在中心视场中，实验研究和模拟研究的这些值分别约为1.3%和1.2%。测量表明，模拟和实验在伽马相机长尺寸方向头部表面的空间分辨率差异不超过4%。短轴方向的差异约为6%。点源和线源图像的半高宽在实验图像和相应模拟图像之间显示出良好的一致性。实验和模拟系统参数之间的差异在11%以内。我们的结果表明，通过为数字化仪链和探测器表面的准直器位置选择合适的参数，蒙特卡罗模拟能够灵活地对带有位置灵敏探测器的像素化伽马相机进行建模。
