A positron emission tomography (PET) technique that can enhance the image resolution and system sensitivity of a clinical PET/CT scanner for imaging a whole body or a target region of a subject is provided. The system includes a detector array and a detector panel. The detector array includes an array of gamma ray detectors defining a field of view of a scanner and configured to detect at least one coincidence event. The detector panel includes an array of gamma ray detectors having a higher intrinsic spatial resolution than the detector array and positioned in closer proximity to a patient table than the detector array. The detector panel is positioned outside the field of view defined by the detector array during at least a portion of scanning by the PET system. The detector panel is configured to detect at least one coincidence event in cooperation with the detector array. The control unit is configured to control the detector array, the detector panel, and the patient bed to operate in cooperation with each other.
