Proposal of a New Step-Angle Acquisition Method for Triple-Detector SPECT Systems

Abstract

In SPECT, off-set acquisition method can reduce the total number of projections. However, no clinical systems have been developed to support this, because a special mechanism is required to shift the detector slightly from even intervals. In this study, we proposed a novel acquisition method for triple-detector, and investigated its effectiveness. The proposed method changes the step angle only once without acquiring opposite data, and projection data are arranged at even intervals in consideration of the opposite data. Therefore, the need for a special mechanism is eliminated. The projection data were generated using a Monte Carlo simulation, considering factors such as scatter, attenuation, and collimator aperture. Images were reconstructed using ML-EM. Although there were no significant differences in spatial resolution, the NRMSE of the proposed method with an even number of projections (less than 24) was better than that of the conventional method. The proposed method obtained accurate reconstructed images because the projection data of the proposed method were balanced at 360° to avoid distortion.