Imaging system sag correction method and apparatus

An apparatus for use with a single modality imaging system configured to generate uncorrected imaging data of a patient, the single modality imaging system includes two gamma cameras and a patient stretcher disposed between the two gamma cameras, the apparatus for compensating for downward stretcher deflection at the extended end of the patient stretcher that occurs during stretcher extension. The apparatus includes a single sag sensor for sensing the downward deflection of the patient stretcher, a subtracting device configured to generate a sag correction factors based on a baseline stretcher height and an input received from the sag sensor, and a compensator configured to modify at least a portion of the uncorrected imaging data to compensate for sag using the sag correction factor to generate a unified image.