Abstract: Systems and methods for image reconstruction are provided. A method may include obtaining image data that includes information of a plurality of coincidence events; for each of the plurality of coincidence events, identifying, based on the information of the coincidence event, identities of two original scintillator elements at each of which a photon of the coincidence event was detected; obtaining a depth of interaction (DOI) of each photon of the coincidence event within one original scintillator element of the two original scintillator elements; and determining, based on the identities and the DOIs of the two original scintillator elements, identities of two corrected scintillator elements each of which corresponds to an original scintillator element of the two original scintillator elements; and generating a reconstructed image based on the identities of two corrected scintillator elements of each of the plurality of coincidence events.