1. A method of correcting for at least one of deadtime losses and random coincidences in a positron emission tomography (PET) medical imaging device having a plurality of detectors at successive locations circumferentially spaced about a viewing area, said method comprising: receiving signals indicative of positron-electron annihilation events occurring along a line of response between pairs of detectors for a plurality of predetermined time segments of data acquisition of said events; calculating a correction sinogram for each predetermined time segment from data acquired during each respective single time segment; calculating corrected counts in the correction sinogram for each time segment; calculating a time-weighted correction sinogram for each time segment; combining the time-weighted correction sinograms to generate an acquisition sinogram; and generating an image from the acquisition sinogram.