A method and system for acquiring a series of medical images includes a plurality of detectors configured to be arranged to acquire gamma rays emitted from a subject as a result of an advanced radionuclide administered to the subject and communicate signals corresponding to acquired gamma rays. A data processing system is configured to receive the signals from the plurality of detectors, determine double coincidence event dataset and a multiple coincidence event dataset, separate the multiple coincidence event dataset into at least one of a standard lines of response dataset and a nonstandard lines of response dataset, and apply a background correction to the double coincidence event dataset based on the non-standard lines of response dataset and/or the standard lines of response dataset to obtain a standard coincidence dataset.