Pixel identification for small pitch scintillation crystal arrays

A calibration module for a gamma ray detector including a scintillator array for emitting scintillation photons at photo conversion positions in response to incident gamma rays and a photodetector array coupled thereto in light-sharing mode for determining a spatial intensity distribution of scintillation photons, said module comprising:

• a recorder for recording spatial intensity distributions of scintillation photons emitted by the scintillator array in response to multiple incident gamma rays;
• a computer configured to:
• determine sets of coincidently emitted scintillation photons from the recorded spatial intensity distributions, determine for the sets of coincidently emitted scintillation photons center-of-gravity positions and cumulative energies, perform a clustering analysis based on the determined center-of-gravity positions and cumulative energies to obtain clusters of gamma ray events attributed to a scintillator array element, cumulate for a cluster the spatial intensity distributions to determine a cumulative spatial intensity distribution of scintillation photons emitted in response to incident gamma rays in the scintillator array element, and
• determine a light matrix including expected spatial intensity distributions of scintillation photons for different scintillator array elements based on the cumulative spatial intensity distributions.

A non-transitory computer-readable medium carrying program code configured to control a computer to:

• record spatial intensity distributions of scintillation photons from a gamma ray detector including a scintillator array which emits scintillation photons at photo conversion positions in response to incident gamma rays and a photodetector array coupled thereto in light-sharing mode which determines the spatial intensity distribution of scintillation photons,
• determine sets of coincidently emitted scintillation photons from the recorded spatial intensity distributions;
• determine for the sets of coincidently emitted scintillation photons center-of-gravity positions and cumulative energies;
• perform a clustering analysis based on the determined center-of-gravity positions and cumulative energies to obtain clusters of gamma ray events attributed to a scintillator array element;
• cumulate for a cluster the spatial intensity distributions to determine a cumulative spatial intensity distribution of scintillation photons emitted in response to incident gamma rays in the scintillator array element;
• determine a light matrix including expected spatial intensity distributions of scintillation photons for different scintillator array elements based on the cumulative spatial intensity distributions;
• generate spatial intensity distributions from gamma rays received from an imaged subject with the gamma ray detector;
• operate on the spatial intensity distributions using the light matrix to generate corrected spatial intensity distributions;
• reconstruct the corrected spatial intensity distributions in a diagnostic image of the imaged subject.

A gamma detector comprising:

• a scintillator array configured to emit scintillation photons in response to incident gamma radiation;
• a photodetector array coupled to the scintillator array in a light sharing mode;
• one or more computer processors configured to:
• determine spatial intensity distributions of the scintillation photons emitted by the scintillator array in response to incident gamma radiation,
• determine sets of coincidently emitted scintillation photons from the spatial intensity distributions,
• determine for the sets of coincidently emitted scintillation photons center-of-gravity positions and cumulative energies,
• perform a clustering analysis based on the determined center of gravity positions and the cumulative energies to obtain clusters of gamma events attributed to a scintillator array element,
• cumulate the spatial intensity distributions for the cluster to determine a cumulative spatial intensity distribution of scintillation photons emitted in response to incident gamma radiation in the scintillator array element, and
• generate a light matrix indicative of an expected spatial intensity distribution of scintillation photons for each scintillator element of the scintillator array based on the cumulative spatial intensity distributions.