Nakajima K, Shuke N, Taki J, Ichihara T, Motomura N, Bunko H, Hisada K
Department of Nuclear Medicine, Kanazawa University Hospital, Tochigi, Japan.
J Nucl Med. 1992 Jun;33(6):1200-6.
Data acquisition in SPECT assumes that there is no change in radionuclide distribution during data collection. However, this assumption is not valid in radiopharmaceuticals with rapid temporal changes in radioactivity. Artifacts and quantitative errors are studied using phantom studies, mathematical models, and clinical myocardial data. Projection data of each model were sequentially multiplied by weighting coefficients that varied mono-exponentially with time, and the SPECT images were reconstructed. A long data acquisition time in comparison to the clearance of the tracer can be a significant cause of artifact. When the myocardial septum-to-lateral count ratio is used as an index of distortion, a shorter acquisition time than the effective half-life of the tracer is required to reduce the error of the septum-to-lateral count ratio to within 10%. Since 180 degrees rotation acquisition causes artifacts depending on the direction of rotation, 360 degrees acquisition is preferable. Continuous repetitive rotation acquisition is a suitable method for dynamic SPECT to reduce quantitative errors and artifacts.
单光子发射计算机断层扫描（SPECT）中的数据采集假定在数据收集期间放射性核素分布没有变化。然而，对于放射性随时间快速变化的放射性药物，这一假设并不成立。使用体模研究、数学模型和临床心肌数据来研究伪影和定量误差。每个模型的投影数据依次乘以随时间呈单指数变化的加权系数，然后重建SPECT图像。与示踪剂清除相比，较长的数据采集时间可能是伪影的一个重要原因。当使用心肌间壁与侧壁计数比作为畸变指标时，需要比示踪剂有效半衰期更短的采集时间，以将间壁与侧壁计数比的误差降低到10%以内。由于180度旋转采集会根据旋转方向产生伪影，因此360度采集更可取。连续重复旋转采集是动态SPECT减少定量误差和伪影的合适方法。
