Jin Yifei, Zannoni E M, Meng Ling-Jian
Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801 USA.
Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801 USA. She is now with the Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712 USA.
IEEE Trans Radiat Plasma Med Sci. 2025 May;9(5):553-563. doi: 10.1109/trpms.2024.3520668. Epub 2024 Dec 24.
This study introduces a novel maximum-likelihood-based data preconditioning method for a 3-D position sensitive cadmium zinc telluride (CZT) detector used in the dynamic extremity-single photon emission computed tomography imaging system, an organ-dedicated Single-Photon Emission computed tomography system optimized for imaging peripheral vascular diseases in lower extremities. The 3-D CZT detectors offer subpixel resolution of ~0.5 mm FWHM in directions and an ultrahigh energy resolution of 3 keV at 200 keV, 4.5 keV at 450 keV, and 5.4 keV at 511 keV. Given the intrinsic challenges posed by pixel boundary issues, spatial distortions, and nonuniformity inherent in large-volume, high-resolution CZT detectors, we proposed a Maximum-Likelihood-based preconditioning technique to reconstruct the projection, which effectively mitigates the pixel boundary issue and deconvolves the distortions and nonuniformity in detector responses. To facilitate the preconditioning step, we used sheet-beam scanning to measure the distortion map of the CZT detectors. We have evaluated our data preconditioning technique through extensive experimental evaluations, including Tc-99m sheet-beam scanning and image reconstruction of an image quality phantom. These results not only demonstrated the efficacy of the technique in reducing the impact of pixel boundary issues and correcting for spatial distortions. The proposed data preconditioning technique could potentially be applied across various types of imaging sensors.
本研究为动态肢体单光子发射计算机断层成像系统中使用的三维位置敏感碲锌镉（CZT）探测器引入了一种基于最大似然的数据预处理新方法，该系统是一种专门用于成像下肢周围血管疾病的器官专用单光子发射计算机断层成像系统。三维CZT探测器在各方向上提供约0.5毫米半高宽的亚像素分辨率，在200 keV时能量分辨率为3 keV，在450 keV时为4.5 keV，在511 keV时为5.4 keV。鉴于大体积、高分辨率CZT探测器固有的像素边界问题、空间畸变和不均匀性带来的内在挑战，我们提出了一种基于最大似然的预处理技术来重建投影，该技术有效地减轻了像素边界问题，并对探测器响应中的畸变和不均匀性进行反卷积。为便于进行预处理步骤，我们使用片状束扫描来测量CZT探测器的畸变图。我们通过广泛的实验评估对我们的数据预处理技术进行了评估，包括Tc-99m片状束扫描和图像质量体模的图像重建。这些结果不仅证明了该技术在减少像素边界问题的影响和校正空间畸变方面的有效性。所提出的数据预处理技术可能潜在地应用于各种类型的成像传感器。
