Optimization of pinhole SPECT calibration

Previously, we developed a method to determine the acquisition geometry of a pinhole camera. This information is needed for the correct reconstruction of pinhole SPECT images. The method uses a calibration phantom consisting of three point sources. Their positions in the field of view influence the accuracy of the geometry estimate. This study proposes a specific configuration of point sources with a specific position in the field of view for optimal image reconstruction accuracy. For the proposed calibration setup, inaccuracies of the geometry estimate due to noise in the calibration data, only cause sub-resolution inaccuracies in reconstructed images. Further, the calibration method uses a model of the point source configuration, which is only known with limited accuracy. The study demonstrates however, that, with the proposed calibration setup, the error in reconstructed images is comparable to the error in the phantom model.