In Single Photon Emission Computed Tomography (SPECT) projections over 2π with non-uniform attenuation contain redundant information thus the scanning angle can be reduced to π which can be used to improve the imaging quality. The precondition of this reduction is the application of correction for gamma photon attenuation and the distance dependent spatial resolution of the detector during reconstruction. Despite the existing redundancy in the projections in opposite directions they cannot be treated identically because of statistical differences of the corresponding views. In this work we propose a new approximation method to select an optimal set of views over π with the best statistical properties. Using this set of views during the data acquisition the image quality can be improved. The paper also contains the verification and evaluation results of the proposed approximation method using a mathematical and two realistic physical phantoms. 
Practical estimation method of the optimal scanning protocol for 180° data acquisition in parallel SPECT imaging