DETECTOR HEAD POSITION CALIBRATION AND CORRECTION FOR SPECT IMAGING APPARATUS USING VIRTUAL CT

A multiple point source test phantom is used for calibration of detector positioning of a nuclear medical imaging apparatus. An absolute coordinate system for the detectors is aligned to an image reconstruction space coordinate system by fitting a Gaussian surface to a peak of a center point source of said test phantom, and using displacement parameters as obtained from the fitted Gaussian surface to calculate a displacement correction parameter, which is used to move a patient bed of the imaging apparatus such that the image reconstruction space is aligned with the absolute coordinate system.