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Impact of aperture-thickness on the real-time imaging characteristics of coded-aperture gamma cameras
Nuclear Engineering and Technology ( IF 2.7 ) Pub Date : 2020-09-01 , DOI: 10.1016/j.net.2020.09.012
Seoryeong Park , Jiwhan Boo , Mark Hammig , Manhee Jeong

Abstract The mask parameters of a coded aperture are critical design features when optimizing the performance of a gamma-ray camera. In this paper, experiments and Monte Carlo simulations were performed to derive the minimum detectable activity (MDA) when one seeks a real-time imaging capability. First, the impact of the thickness of the modified uniformly redundant array (MURA) mask on the image quality is quantified, and the imaging of point, line, and surface radiation sources is demonstrated using both cross-correlation (CC) and maximum likelihood expectation maximization (MLEM) methods. Second, the minimum detectable activity is also derived for real-time imaging by altering the factors used in the image quality assessment, consisting of the peak-to-noise ratio (PSNR), the normalized mean square error (NMSE), the spatial resolution (full width at half maximum; FWHM), and the structural similarity (SSIM), all evaluated as a function of energy and mask thickness. Sufficiently sharp images were reconstructed when the mask thickness was approximately 2 cm for a source energy between 30 keV and 1.5 MeV and the minimum detectable activity for real-time imaging was 23.7 MBq at 1 m distance for a 1 s collection time.

中文翻译:

孔径厚度对编码孔径伽马相机实时成像特性的影响

摘要 编码孔径的掩模参数是优化伽马射线相机性能的关键设计特征。在本文中,当人们寻求实时成像能力时,进行了实验和蒙特卡罗模拟以推导出最小可检测活动 (MDA)。首先,量化了修改后的均匀冗余阵列 (MURA) 掩模的厚度对图像质量的影响,并使用互相关 (CC) 和最大似然期望证明了点、线和面辐射源的成像最大化 (MLEM) 方法。其次,通过改变图像质量评估中使用的因素,包括峰噪比 (PSNR)、归一化均方误差 (NMSE)、空间分辨率(半高全宽;FWHM)和结构相似性(SSIM),都作为能量和掩模厚度的函数进行评估。当源能量介于 30 keV 和 1.5 MeV 之间的掩模厚度约为 2 cm 时,重建足够清晰的图像,并且实时成像的最小可检测活动为 1 m 距离下 1 s 收集时间的最小可检测活动为 23.7 MBq。
更新日期:2020-09-01
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