For multi-pinhole SPECT, iterative reconstruction algorithms are preferred over analytical methods, because of the often complex multi-pinhole geometries and the ability of iterative algorithms to compensate for effects like spatially variant sensitivity and resolution. Ideally such compensation methods are based on accurate knowledge of the position-dependent point spread functions (PSFs) specifying the response of the detectors to a point source at every position in the instrument. This paper describes a method for model-based generation of complete PSF lookup tables from a limited number of point source measurements for stationary SPECT systems and its application to a sub-mm resolution stationary small-animal SPECT system containing 75 109