An emission tomography system and method are used to acquire a series of medical images of a subject during an imaging process using a radiotracer. The system includes detectors for acquiring gamma rays emitted from the subject after administration of the radiotracer. A stimulus system tracks a stimulus associated with the subject during imaging. A data processing system receives signals from the detectors and stimulus feedback from the stimulus system and correlates the signals with information about the stimulus associated with the subject. A reconstruction system receives the correlated signals and information about the stimulus from the data processing system and reconstructs a series of medical images of the subject showing a physiological response of the subject to the stimulus over a time period.