Abstract: A method and apparatus are provided for positron emission imaging to correct a recorded energy of a detected gamma ray, when the gamma ray is scattered during detection. When scattering occurs, the energy of a single gamma ray can be distributed across multiple detector elements—a multi-channel detection. Nonlinearities in the detection process and charge/light sharing among adjacent channels can result in the summed energies from the multiple crystals of a multi-channel detection deviating from the energy that would be measured in single-channel detection absent scattering. This deviation is corrected by applying one or more correction factors (e.g., multiplicative or additive) that shifts the summed energies of multi-channel detections to agree with a known predefined energy (e.g., 511 keV). The correction factors can be stored in a look-up-table that is segmented to accommodate variations in the multi-channel energy shift based on the level of energy sharing.

Abstract: A method and apparatus are provided for positron emission imaging to correct a recorded energy of a detected gamma ray, when the gamma ray is scattered during detection. When scattering occurs, the energy of a single gamma ray can be distributed across multiple detector elements—a multi-channel detection. Nonlinearities in the detection process and charge/light sharing among adjacent channels can result in the summed energies from the multiple crystals of a multi-channel detection deviating from the energy that would be measured in single-channel detection absent scattering. This deviation is corrected by applying one or more correction factors (e.g., multiplicative or additive) that shifts the summed energies of multi-channel detections to agree with a known predefined energy (e.g., 511 keV). The correction factors can be stored in a look-up-table that is segmented to accommodate variations in the multi-channel energy shift based on the level of energy sharing.

Abstract: A method of arranging detector modules within a gamma ray detector apparatus, each detector module including an array of scintillation crystals to convert light into electrical signals, the light being generated in response to incident gamma rays generated by an annihilation event, the method including obtaining performance information of each of the detector modules, and determining a relative location for each of the detector modules within the gamma ray detector based on the obtained performance information of the detector modules.

Abstract: Systems, devices, processes, and algorithms for adapting and/or adjusting a reflectivity of a reflector in a radiation detector. The reflectivity can be changed by a reflectivity control signal that is generated based on an estimated count rate of events so as to adjust a probability of a photosensor detecting light resulting from the event via, for example, a scintillation event. By adjusting the probability, an energy resolution of the radiation detector can be optimized. The reflectivity of a reflector can be changed by changing a state of a thin film, a liquid crystal layer, or a suspended magnetic particle layer.

Abstract: A method to improve light extraction from scintillators in a gamma ray detector, the method including forming a roughened layer on a light-emitting surface of the scintillators, the roughened thin layer having a pillar/column or a corn-shaped structure.

Abstract: A process and system including a detector having a photosensor therein that outputs a signal and a plurality of after-pulse detector devices independently connected to the photosensor via respective pathways. The after-pulse detector devices each detecting an after-pulse in the signal, where the after-pulse represents an after-event in the photosensor triggered from a previous photon generating event. The system further includes a processing device that receives an indication of the detection of the after-pulse from each of the plurality of after-pulse detector devices and determines a relative delay between the respective pathways based on timing the received indications, and includes a memory that stores the relative delay in association with an identification of the corresponding after-pulse detector devices.

Abstract: A process and system including a detector having a photosensor therein that outputs a signal and a plurality of after-pulse detector devices independently connected to the photosensor via respective pathways. The after-pulse detector devices each detecting an after-pulse in the signal, where the after-pulse represents an after-event in the photosensor triggered from a previous photon generating event. The system further includes a processing device that receives an indication of the detection of the after-pulse from each of the plurality of after-pulse detector devices and determines a relative delay between the respective pathways based on timing the received indications, and includes a memory that stores the relative delay in association with an identification of the corresponding after-pulse detector devices.

Abstract: A process and system including a detector having a photosensor therein that outputs a signal and a plurality of after-pulse detector devices independently connected to the photosensor via respective pathways. The after-pulse detector devices each detecting an after-pulse in the signal, where the after-pulse represents an after-event in the photosensor triggered from a previous photon generating event. The system further includes a processing device that receives an indication of the detection of the after-pulse from each of the plurality of after-pulse detector devices and determines a relative delay between the respective pathways based on timing the received indications, and includes a memory that stores the relative delay in association with an identification of the corresponding after-pulse detector devices.

Abstract: A photosensor gain detection apparatus that includes a detector including a photosensor configured to output a signal. Also included in the apparatus is an after-pulse/dark-pulse detector device that detects an after-pulse or a dark-pulse in the signal output by the photosensor, and outputs an indication signal when the after-pulse or the dark-pulse is detected, the after-pulse and the dark-pulse representing after-events in the photosensor triggered from a previous photon generating event. The apparatus additionally includes an integrator device that integrates the signal output by the photosensor and to output an integrated signal, a histogram device connected to the integrator and the after-pulse/dark-pulse detector device, and that generates a histogram from the integrated signal and the indication signal, a gain determination device that determines a gain of the photosensor based on the generated histogram, and a memory configured to store the determined gain.

Abstract: A method and system for calibrating an imaging system in which a positron-emitting radioisotope source is arranged in or adjacent to an imaging region of the imaging system, an annihilation target is arranged at a position separated from the positron-emitting radioisotope source by a predetermined distance, coincident event pairs resulting from annihilation of positrons at the annihilation target are detected, a calibration time offset for a detector element in the imaging system is calculated based on the detected coincident event pairs, and the detector element is calibrated with the completed calibration time offset.

Abstract: Systems, devices, processes, and algorithms for adapting and/or adjusting a reflectivity of a reflector in a radiation detector. The reflectivity can be changed by a reflectivity control signal that is generated based on an estimated count rate of events so as to adjust a probability of a photosensor detecting light resulting from the event via, for example, a scintillation event. By adjusting the probability, an energy resolution of the radiation detector can be optimized. The reflectivity of a reflector can be changed by changing a state of a thin film, a liquid crystal layer, or a suspended magnetic particle layer.

Abstract: A photosensor gain detection apparatus that includes a detector including a photosensor configured to output a signal. Also included in the apparatus is an after-pulse/dark-pulse detector device that detects an after-pulse or a dark-pulse in the signal output by the photosensor, and outputs an indication signal when the after-pulse or the dark-pulse is detected, the after-pulse and the dark-pulse representing after-events in the photosensor triggered from a previous photon generating event. The apparatus additionally includes an integrator device that integrates the signal output by the photosensor and to output an integrated signal, a histogram device connected to the integrator and the after-pulse/dark-pulse detector device, and that generates a histogram from the integrated signal and the indication signal, a gain determination device that determines a gain of the photosensor based on the generated histogram, and a memory configured to store the determined gain.

Abstract: A method of arranging detector modules within a gamma ray detector apparatus, each detector module including an array of scintillation crystals to convert light into electrical signals, the light being generated in response to incident gamma rays generated by an annihilation event, the method including obtaining performance information of each of the detector modules, and determining a relative location for each of the detector modules within the gamma ray detector based on the obtained performance information of the detector modules.

Abstract: A process and system including a detector having a photosensor therein that outputs a signal and a plurality of after-pulse detector devices independently connected to the photosensor via respective pathways. The after-pulse detector devices each detecting an after-pulse in the signal, where the after-pulse represents an after-event in the photosensor triggered from a previous photon generating event. The system further includes a processing device that receives an indication of the detection of the after-pulse from each of the plurality of after-pulse detector devices and determines a relative delay between the respective pathways based on timing the received indications, and includes a memory that stores the relative delay in association with an identification of the corresponding after-pulse detector devices.

Abstract: A method to improve light extraction from scintillators in a gamma ray detector, the method including forming a roughened layer on a light-emitting surface of the scintillators, the roughened thin layer having a pillar/column or a corn-shaped structure.