1. A nuclear camera calibration system, including: a nuclear camera that images a radiopharmaceutical point source and scans a radiopharmaceutical tracer sample; and a processor that: generates a nuclear image of a point source of the radiopharmaceutical tracer sample from acquired nuclear scan data; compares a measured PSF from the nuclear image to the calibrated PSF; compares a measured point spread function (PSF) from a point source image to a simulated PSF to determine a difference value therebetween; generates a PSF correction curve by interpolating PSF data for the measured PSF to reduce the difference value using the simulated PSF; calibrates the measured PSF to generate a calibrated PSF; stores the calibrated PSF to a memory; adjusts one or more calibration parameters to estimate a level of off-energy contamination in the tracer sample; employing the adjusted parameters, combines the calibrated PSF and a simulated PSF for the radiopharmaceutical tracer sample; estimates weighting factors for the calibrated PSF; and at least one of recalibrates the calibrated PSF and calibrates the measured PSF using the weighting factors.