Performance Evaluation of a Preclinical SPECT Scanner with a Collimator Designed for Medium-Sized Animals. (16th July 2022)

• Record Type: Journal Article
• Authors: Matsusaka, Yohji; Werner, Rudolf A.; Arias-Loza, Paula; Nose, Naoko; Sasaki, Takanori; Chen, Xinyu; Lapa, Constantin; Higuchi, Takahiro
• Other Names: VanBrocklin Henry Academic Editor.
• Is Part Of: Molecular imaging. Volume 2022(2022)
• Publication Date: 2022-07-16
• Subjects: Molecular diagnosis -- Periodicals; Diagnostic imaging -- Periodicals; Molecular biology -- Periodicals; Molecular diagnosis; Diagnostic imaging; Molecular biology; Periodicals; 616.075
• DOI: 10.1155/2022/9810097
• Languages: English
• ISSNs: 1535-3508

Abstract

Abstract : Background . Equipped with two stationary detectors, a large bore collimator for medium-sized animals has been recently introduced for dedicated preclinical single-photon emission computed tomography (SPECT) imaging. We aimed to evaluate the basic performance of the system using phantoms and healthy rabbits. Methods . A general-purpose medium-sized animal (GP-MSA) collimator with 135 mm bore diameter and thirty-three holes of 2.5 mm diameter was installed on an ultrahigh-resolution scanner equipped with two large stationary detectors (U-SPECT5-E/CT). The sensitivity and uniformity were investigated using a point source and a cylinder phantom containing 99m Tc-pertechnetate, respectively. Uniformity (in %) was derived using volumes of interest (VOIs) on images of the cylinder phantom and calculated as maximum count − minimum count / maximum count + minimum count × 100, with lower values of % indicating superior performance. The spatial resolution and contrast-to-noise ratios (CNRs) were evaluated with images of a hot-rod Derenzo phantom using different activity concentrations. Feasibility of in vivo SPECT imaging was finally confirmed by rabbit imaging with the most commonly used clinical myocardial perfusion SPECT agent [ 99m Tc]Tc-sestamibi (dynamic acquisition with a scan time of 5 min). Results . In the performance evaluation, a sensitivity of 790 cps/MBq, a spatial resolution with the hot-rod phantom of 2.5 mm, and a uniformity of 39.2% were achieved. The CNRs of the rod size 2.5 mm were 1.37, 1.24, 1.20, and 0.85 for activity concentration of 29.2, 1.0, 0.5, and 0.1 MBq/mL, respectively. Dynamic SPECT imaging in rabbits allowed to visualize most of the thorax and to generate time-activity curves of the left myocardial wall and ventricular cavity. Conclusion . Preclinical U-SPECT5-E/CT equipped with a large bore collimator demonstrated adequate sensitivity and resolution for in vivo rabbit imaging. Along with its unique features of SPECT molecular functional imaging is a superior collimator technology that is applicable to medium-sized animal models and thus may promote translational research for diagnostic purposes and development of novel therapeutics.