Abstract: Time of flight (TOF) corrections for radiation detector elements of a TOF positron emission tomography (TOF PET) scanner are generated by solving an over-determined set of equations defined by calibration data acquired by the TOF PET scanner from a point source located at an isocenter of the TOF PET scanner, suitably represented as matrix equation at ?t=CS where ?t represents TOF time differences, C is a relational matrix encoding the radiation detector elements, and S represents the TOF corrections. A pseudo-inverse C?1 of relational matrix C may be computed to solve S=C?1 ?t. TOF corrections can be generated for a particular type of detector unit by identifying the radiation detector elements in C by detector unit. Further, multi-photon triggering time stamps can be adjusted to first-photon triggering based on ?{square root over (P1/Pm)} where P1 is average photon count using first-photon triggering and Pm is a photon count using multi-photon triggering.

Abstract: Time of flight (TOF) corrections for radiation detector elements of a TOF positron emission tomography (TOF PET) scanner are generated by solving an over-determined set of equations defined by calibration data acquired by the TOF PET scanner from a point source located at an isocenter of the TOF PET scanner, suitably represented as matrix equation ?t=CS where ?t represents TOF time differences, C is a relational matrix encoding the radiation detector elements, and S represents the TOF corrections. A pseudo-inverse C?1 of relational matrix C may be computed to solve S=C?1?t. TOF corrections can be generated for a particular type of detector unit by identifying the radiation detector elements in C by detector unit. Further, multi-photon triggering time stamps can be adjusted to first-photon triggering based on ?{square root over (P1/Pm)} where P1 is average photon count using first-photon triggering and Pm is a photon count using multi-photon triggering.

Abstract: The present application relates generally to positron emission tomography (PET). It finds particular application in conjunction with energy calibration of a digital PET (DPET) detector and will be described with particular reference thereto. In one aspect, a difference spectrum is produced by finding a difference between a background radiation spectrum with no radioactive source loaded and a calibration source radiation spectrum with a radioactive source loaded. The difference spectrum may then be used to identify an energy peak.

Abstract: Time of flight (TOF) corrections for radiation detector elements of a TOF positron emission tomography (TOF PET) scanner are generated by solving an over-determined set of equations defined by calibration data acquired by the TOF PET scanner from a point source located at an isocenter of the TOF PET scanner, suitably represented as matrix equation Formula I=CS where Formula I represents TOF time differences, C is a relational matrix encoding the radiation detector elements, and S represents the TOF corrections. A pseudo-inverse C?1 of relational matrix C may be computed to solve S=C?1 Formula I. TOF corrections can be generated for a particular type of detector unit by identifying the radiation detector elements in C by detector unit. Further, multi-photon triggering time stamps can be adjusted to first-photon triggering based on Formula II where P1 is average photon count using first-photon triggering and Pm is a photon count using multi-photon triggering.

Abstract: A system (10) and method for energy correction of positron emission tomography (PET) event data by at least one processor. Event data for a plurality of strike events corresponding to gamma events is received. Each strike event is detected by a pixel of a detector module (50) and includes an energy and a time. The energy of the strike events is linearized using an energy linearity correction model including one or more parameters. Clusters of the strike events are identified based on the times of the strike events, and sub-clusters of the clusters are identified based on the pixels corresponding to the strike events of the clusters. Energies of the sub-clusters are corrected using a first set of correction factors, and energies of clusters including a plurality of sub-clusters are corrected using a second set of correction factors.

Abstract: The present application relates generally to positron emission tomography (PET). It finds particular application in conjunction with energy calibration of a digital PET (DPET) detector and will be described with particular reference thereto. In one aspect, a difference spectrum is produced by finding a difference between a background radiation spectrum with no radioactive source loaded and a calibration source radiation spectrum with a radioactive source loaded. The difference spectrum may then be used to identify an energy peak.

Abstract: A system (10) and a method (100) compensate for one or more dead pixels in positron emission tomography (PET) imaging. A pixel compensation processor receives PET data describing a target volume of a subject. The PET data is missing data for one or more dead pixels. The pixel compensation estimates PET data for the dead pixels from the received PET data.

Abstract: A diagnostic imaging system includes a plurality of radiation detectors (20) configured to detect radiation events emanating from an imaging region. The system includes a calibration phantom (14) configured to be disposed in the imaging region spanning substantially an entire field of view and to generate radiation event pairs that define lines-of-response, wherein the calibration phantom is thin such that each LOR intersects the calibration phantom along its length, the thickness of the phantom being smaller than the length of the LORs. A calibration processor (24) receives input of the radiation detectors and calculates an incidence angle independent crystal delay Ti for each detector. The calibration processor (24) constructs a first look-up table for the timing correction of each LOR and a second look-up table for the angle depth of interaction correction for each crystal by combining Ti and ?i.

Abstract: A diagnostic imaging system comprises a plurality of radiation detectors (20) configured to detect radiation events emanating from an imaging region. The system comprises a calibration phantom (14) configured to be disposed in the imaging region spanning substantially an entire field of view and to generate radiation event pairs that define lines-of-response, wherein the calibration phantom is thin such that each LOR intersects the calibration phantom along its length, the thickness of the phantom being smaller than the length of the LORs. A calibration processor (24) receives input of the radiation detectors and calculates an incidence angle independent crystal delay ?i for each detector.

Abstract: Time of flight (TOF) corrections for radiation detector elements of a TOF positron emission tomography (TOF PET) scanner are generated by solving an over-determined set of equations defined by calibration data acquired by the TOF PET scanner from a point source located at an isocenter of the TOF PET scanner, suitably represented as matrix equation Formula I=CS where Formula I represents TOF time differences, C is a relational matrix encoding the radiation detector elements, and S represents the TOF corrections. A pseudo-inverse C?1 of relational matrix C may be computed to solve S=C?1 Formula I. TOF corrections can be generated for a particular type of detector unit by identifying the radiation detector elements in C by detector unit. Further, multi-photon triggering time stamps can be adjusted to first-photon triggering based on Formula II where P1 is average photon count using first-photon triggering and Pm is a photon count using multi-photon triggering.

Abstract: A system (10) and a method (100) compensate for one or more dead pixels in positron emission tomography (PET) imaging. A pixel compensation processor receives PET data describing a target volume of a subject. The PET data is missing data for one or more dead pixels. The pixel compensation estimates PET data for the dead pixels from the received PET data.

Abstract: A medical nuclear imaging system (10) and corresponding method (100) are provided. A plurality of pixels (20, 24) detect radiation events and estimate the energy of the detected radiation events. A memory (58) stores a plurality of energy windows (44), the energy windows corresponding to the pixels. An event verification module (56) windows the radiation event with the energy windows corresponding to the detecting pixels. A reconstruction processor (60) reconstructs the windowed radiation events into an image representation.

Abstract: A detector (16) maintains thermal stability between two different operating modes. The detector (16) includes at least one controller (36, 38) which sets the detection sensitivity of the detector (16) to a level disabling the detection of gamma photons. The controller (36, 38) further controls a heat generator (36, 38, 86) to maintain the temperature of the detector (16) at a predetermined temperature. The predetermined temperature is the steady state temperature of the detector (16) when the detection sensitivity of the detector (16) is set to a level enabling the detection of gamma photons. A method (100) for maintaining thermal stability of a detector (16) between two different operating modes is also provided.

Abstract: A medical nuclear imaging system (10) and corresponding method (100) are provided. A plurality of pixels (20, 24) detect radiation events and estimate the energy of the detected radiation events. A memory (58) stores a plurality of energy windows (44), the energy windows corresponding to the pixels. An event verification module (56) windows the radiation event with the energy windows corresponding to the detecting pixels. A reconstruction processor (60) reconstructs the windowed radiation events into an image representation.

Abstract: A detector maintains thermal stability between two different operating modes. The detector includes at least one controller which sets the detection sensitivity of the detector to a level disabling the detection of gamma photons. The controller further controls a heat generator to maintain the temperature of the detector at a predetermined temperature. The predetermined temperature is the steady state temperature of the detector when the detection sensitivity of the detector is set to a level enabling the detection of gamma photons. A method for maintaining thermal stability of a detector between two different operating modes is also provided. Approaches are also disclosed for normalize acquired imaging data during image reconstruction using dark current-dependent normalization factors.

Abstract: A detector maintains thermal stability between two different operating modes. The detector includes at least one controller which sets the detection sensitivity of the detector to a level disabling the detection of gamma photons. The controller further controls a heat generator to maintain the temperature of the detector at a predetermined temperature. The predetermined temperature is the steady state temperature of the detector when the detection sensitivity of the detector is set to a level enabling the detection of gamma photons. A method for maintaining thermal stability of a detector between two different operating modes is also provided. Approaches are also disclosed for normalize acquired imaging data during image reconstruction using dark current-dependent normalization factors.

Abstract: A system (10) and method for energy correction of positron emission tomography (PET) event data by at least one processor. Event data for a plurality of strike events corresponding to gamma events is received. Each strike event is detected by a pixel of a detector module (50) and includes an energy and a time. The energy of the strike events is linearized using an energy linearity correction model including one or more parameters. Clusters of the strike events are identified based on the times of the strike events, and sub-clusters of the clusters are identified based on the pixels corresponding to the strike events of the clusters. Energies of the sub-clusters are corrected using a first set of correction factors, and energies of clusters including a plurality of sub-clusters are corrected using a second set of correction factors.

Abstract: A system and tuning method to collaboratively calibrate high voltage DAC values and Photomultiplier Tube DAC values of photomultiplier tubes of a gamma camera so that the detector produces a valid energy spectrum over the entire detector surface. A method for tuning a gamma camera having a plurality of photosensors, exposes the photosensors to scintillation photons corresponding to nuclear radiation of known energy; measures an energy output corresponding to each specific photosensor; calculates an average enemy output of all photosensors in the camera; collaboratively adjusts a DAC value corresponding to a voltage applied to a specific photosensor and a DACHV value corresponding to a high voltage applied to the camera based on the calculated average energy, energy output of each photosensor, and a target energy value corresponding to said known energy; and repeats the calibration until convergence is achieved between the average energy, energy output, and target energy.

Abstract: A method for optimizing the scanning trajectory of a radiation detector device, e.g., a SPECT scanning device, about an object generally includes: obtaining object image data using a different imaging modality, e.g., a CT scanning device, determining a maximum object boundary based on the image data, calculating an optimal scan trajectory of the SPECT scanning device relative to the object based on the maximum object boundary, scanning the object with the SPECT scanning device along the optimal scan trajectory to detect gamma photons emanating from the object, from which an image can be reconstructed from the detected gamma photons. Preferably, the SPECT device includes at least two detectors arranged at a pre-selected angle relative to one another and the optimal scan trajectory minimizes the distance between the detectors and the object while maximizing the geometric efficiency of the detectors relative to the object.

Abstract: A system and tuning method to collaboratively calibrate high voltage DAC values and Photomultiplier Tube DAC values of photomultiplier tubes of a gamma camera so that the detector produces a valid energy spectrum over the entire detector surface. A method for tuning a gamma camera having a plurality of photosensors, exposes the photosensors to scintillation photons corresponding to nuclear radiation of known energy; measures an energy output corresponding to each specific photosensor; calculates an average enemy output of all photosensors in the camera; collaboratively adjusts a DAC value corresponding to a voltage applied to a specific photosensor and a DACHV value corresponding to a high voltage applied to the camera based on the calculated average energy, energy output of each photosensor, and a target energy value corresponding to said known energy; and repeats the calibration until convergence is achieved between the average energy, energy output, and target energy.