System and method for image data processing in positron emission tomography

A method for reconstructing a positron emission tomography (PET) image, comprising:

• obtaining PET data of a subject acquired by a PET device having an axial length, the PET data including position information of a plurality of coincident events, the plurality of coincident events including scattering events and random events, each coincident event being detected by a pair of detector units of the PET device, and the position information of each coincident event including a first detector position and a second detector position of the pair of detector units;
• for each coincident event, determine a detector position difference between the corresponding first detector position and the corresponding second detector position;
• selecting, based on the detector position differences of the plurality of coincident events, a portion of the PET data from the PET data;
• determining, based on the selected portion of the PET data, target correction data relating to the scattering events and the random events;
• and
• reconstructing, based on the PET data and the target correction data, a target image of the subject.

A non-transitory computer readable medium embodying a computer program product, the computer program product comprising instructions configured to cause a computing device to:

• obtain PET data of a subject acquired by a PET device having an axial length, the PET data including position information of a plurality of coincident events, the plurality of coincident events including scattering events and random events, each coincident event being detected by a pair of detector units of the PET device, and the position information of each coincident event including a first detector position and a second detector position of the pair of detector units;
• for each coincident event, determine a detector position difference between the corresponding first detector position and the corresponding second detector position;
• select, based on the detector position differences of the plurality of coincident events, a portion of the PET data from the PET data;
• determine, based on the selected portion of the PET data, target correction data relating to the scattering events and the random events;
• and
• reconstruct, based on the PET data and the target correction data, a target image of the subject.