Method and apparatus to determine energy correction arising from multi-channel detection in a gamma detector exhibiting non-linear energy measurement and/or cross-talk among channels

An imaging apparatus, comprising:

• processing circuitry configured to
• obtain emission data representing positions and energies of gamma rays incident at a plurality of detector elements, detector elements of the plurality of detector elements leaking a part of a gamma-ray detection signal to adjacent detector elements of the plurality of detector elements,
• obtain an energy calibration including one or more correction factors that correct for an energy shift occurring during multi-channel detection in which a primary gamma ray is scattered and an energy of a scattered gamma ray is absorbed in a different detector element of the plurality of detector elements than a detector element absorbing a part of an energy of the primary gamma ray,
• determine which detection events of the emission data correspond to the multi-channel detection to select multi-channel events, and
• apply the one or more correction factors to respective energies of the selected multi-channel events to generate corrected emission data, wherein
• the energy shift is due to cross-talk produced in the multi-channel detection,
• the energy shift is a loss of energy level of the gamma rays,
• the energy calibration includes the one or more correction factors for respective one or more numbers of hits of gamma rays at the plurality of detector elements, and
• the processing circuitry is configured to select the multi-channel events by grouping the multi-channel events in terms of the one or more numbers of hits, and to apply the one or more correction factors to the respective energies of the selected multi-channel events having the corresponding one or more numbers of hits.