Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167, Mannheim, Germany.
Medical Physics and Biophysics Research Group, Physics Department, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok, 16424, Indonesia.
Ann Nucl Med. 2021 Jan;35(1):111-120. doi: 10.1007/s12149-020-01547-7. Epub 2020 Nov 12.
The performance characteristics of the SPECT sub-system S102 of the ALBIRA II PET/SPECT/CT are analyzed for the 80 mm field of view (FOV) to evaluate the potential in-vivo imaging in rats, based on measurements of the system response for the commonly used Technetium-99 m (Tc) in small animal imaging.
The ALBIRA II tri-modal µPET/SPECT/CT pre-clinical system (Bruker BioSpin, Ettlingen, Germany) was used. The SPECT modality is made up of two opposite gamma cameras (Version S102) with Sodium doped Cesium Iodide (CsI(Na)) single continuous crystal detectors coupled to position-sensitive photomultipliers (PSPMTs). Imaging was performed with the NEMA NU-4 image quality phantom (Data Spectrum Corporation, Durham, USA). Measurements were performed with a starting activity concentration of 4.76 MBq/mL Tc. An energy window of 20% at 140 keV was selected in this study. The system offers a 20 mm, 40 mm, 60 mm and an 80 mm field of view (FOV) and in this study the 80 mm FOV was used for all the acquisitions. The data were reconstructed with an ordered subset expectation maximization (OSEM) algorithm. Sensitivity, spatial resolution, count rate linearity, convergence of the algorithm and the recovery coefficients (RC) were analyzed. All analyses were performed with PMOD and MATLAB software.
The sensitivities measured at the center of the 80 mm FOV with the point source were 23.1 ± 0.3 cps/MBq (single pinhole SPH) and 105.6 ± 5.5 cps/MBq (multi pinhole MPH). The values for the axial, tangential and radial full width at half maximum (FWHM) were 2.51, 2.54, and 2.55 mm with SPH and 2.35, 2.44 and 2.32 mm with MPH, respectively. The corresponding RC values for the 5 mm, 4 mm, 3 mm and 2 mm rods were 0.60 ± 0.28, 0.61 ± 0.24, 0.29 ± 0.11 and 0.20 ± 0.06 with SPH and 0.56 ± 0.20, 0.50 ± 0.18, 0.38 ± 0.09 and 0.23 ± 0.06 with MPH. To obtain quantitative imaging data, the image reconstructions should be performed with 12 iterations.
The ALBIRA II preclinical SPECT sub-system S102 has a favorable sensitivity and spatial resolution for the 80 mm FOV setting for both the SPH and MPH configurations and is a valuable tool for small animal imaging.
分析 ALBIRA II PET/SPECT/CT 的 SPECT 子系统 S102 的性能特征，以评估其在大鼠体内成像中的潜在应用，该系统基于常用的小动物成像放射性核素锝-99m（Tc）的系统响应测量。
使用 Bruker BioSpin 公司的 ALBIRA II 三模态 µPET/SPECT/CT 前临床系统（德国埃特林根）。SPECT 模式由两个相对的伽马相机（版本 S102）组成，采用掺钠碘化铯（CsI(Na)）单连续晶体探测器，与位置灵敏光电倍增管（PSPMTs）耦合。成像使用 NEMA NU-4 图像质量体模（美国达勒姆 Data Spectrum 公司）进行。测量采用起始活度浓度为 4.76 MBq/mL 的 Tc。在这项研究中选择了 20%的 140 keV 能量窗。该系统提供 20、40、60 和 80mm 视野（FOV），本研究中所有采集均使用 80mm FOV。数据采用有序子集期望最大化（OSEM）算法重建。分析了灵敏度、空间分辨率、计数率线性度、算法收敛和恢复系数（RC）。所有分析均使用 PMOD 和 MATLAB 软件进行。
使用点源在 80mm FOV 中心测量的灵敏度为 23.1±0.3 cps/MBq（单孔 SPH）和 105.6±5.5 cps/MBq（多孔 MPH）。轴向、切向和径向半高全宽（FWHM）的值分别为 2.51、2.54 和 2.55mm，采用 SPH；2.35、2.44 和 2.32mm，采用 MPH。5、4、3 和 2mm 棒的相应 RC 值分别为 0.60±0.28、0.61±0.24、0.29±0.11 和 0.20±0.06，采用 SPH；0.56±0.20、0.50±0.18、0.38±0.09 和 0.23±0.06，采用 MPH。为了获得定量成像数据，图像重建应使用 12 次迭代进行。
ALBIRA II 临床前 SPECT 子系统 S102 在 SPH 和 MPH 两种配置下均具有良好的 80mm FOV 设置灵敏度和空间分辨率，是小动物成像的有价值工具。
