Methods and systems for imaging a patient are provided. The method includes determining a location of a volume of interest within the patient and acquiring a plurality of frames of emission data, at least one frame including the volume of interest. The method further includes determining a time-of-flight (TOF) information of at least a portion of the annihilations detected along a line of response between corresponding coincidence detectors and generating an image of the patient from the emission data using the determined TOF information.