When calibrating a nuclear camera, such as a SPECT camera, point spread functions (PSF) are simulated for all possible photon energies and detection distances that the camera may experience. During manufacturer-side calibration, a point source (14) is imaged by the nuclear camera and a PSF therefor is measured. The measured PSF is compared to one or more simulated PSFs and a difference therebetween is determined. To calibrate the measured PSF, simulated PSF data is interpolated into the measured PSF to minimize the difference between the measured and simulated PSFs. The calibrated PSF is stored to memory and accessed during user-side calibration. A user then images a tracer sample during a routine camera calibration, and a PSF for the tracer sample is compared to the calibrated PSF to determine a level of contamination in the tracer sample. The tracer sample PSF is then calibrated for use in reconstructing nuclear images.