Siemens Medical Solutions Usa, Inc.

Other

Cti Pet Systems, Inc.

Mehmet Aykac

Vladimir Y Panin

Matthias J Schmand

Ronald Nutt

Niraj K Doshi

Mark Musrock

Lars Aldon Eriksson

James Luke Corbeil

Nan Zhang

Ronald Grazioso

Peter Hansen

Robert A Mintzer

Charles W Williams

Johannes Breuer

Sanghee Cho

James Christopher Arnott

Maciej P Kapusta

Michael D Loope

Shikui Yan

Brian Kelly

Michael E Casey

Mark S Andreaco

Andrew Philip Moor

Ron Grazioso

Carlyle L Reynolds

Systems and methods to estimated mean randoms include acquisition of list mode data describing true coincidences and delay coincidences detected by a positron emission tomography scanner during a scan of an object, determination, for each crystal of the positron emission tomography scanner and for each of a plurality of time periods of the scan, of delay coincidences including the crystal based on the list mode data, determination, each crystal, of determine a singles rate associated with each time period based on the delay coincidences determined for the crystal over the time period, determination, for each time period, of determine estimated mean randoms for each of a plurality of pairs of the crystals based on the singles rate associated with the time period for each crystal of the crystal pair, and reconstruction of an image of the object based on the estimated mean randoms for each time period and the detected true coincidences.

Mean randoms estimation from list mode data

An improved method for time alignment (TA) procedure and crystal efficiency (CE) normalization estimation procedure for a PET scanner system is disclosed. In the TA procedure modeled time-of-flight (TOF) data are compared against the measured TOF data from an axially short cylinder phantom in order to find individual detector's time offsets (TOs). Then the TOs are estimated simultaneously by matching the TOF center of mass between the modeled and measured TOF data. In the CE estimation, TOF reconstruction of CBM data on the axially short cylinder phantom is performed. Alternating between TOF image reconstruction and CE updates eventually lead to the correct estimation of activity and CE component.

Continuous bed motion acquisition with axially short phantom for PET imaging system setup and quality control

A scintillation block detector employs an array of optically air coupled scintillation pixels, the array being wrapped in reflector material and optically coupled to an array of silicon photomultiplier light sensors with common-cathode signal timing pickoff and individual anode signal position and energy determination. The design features afford an optimized combination of photopeak energy event sensitivity and timing, while reducing electronic circuit complexity and power requirements, and easing necessary fabrication methods. Four of these small blocks, or 'miniblocks,' can be combined as optically and electrically separated quadrants of a larger single detector in order to recover detection efficiency that would otherwise be lost due to scattering between them. Events are validated for total energy by summing the contributions from the four quadrants, while the trigger is generated from either the timing signal of the quadrant with the highest energy deposition, the first timing signal derived from the four quadrant time-pickoff signals, or a statistically optimum combination of the individual quadrant event times, so as to maintain good timing for scatter events. This further reduces the number of electronic channels required per unit detector area while avoiding the timing degradation characteristic of excessively large SiPM arrays.

Silicon photomultiplier based TOF-PET detector

Systems and methods to determine random coincidence rates include determination of a detector rate for each of a plurality of detectors of a positron emission tomography scanner based on a frame of positron emission tomography data, determination of a sensitivity for each detector crystal of the plurality of detectors, based on the detector rate of the detector including the detector crystal, determination of a singles rate for each detector crystal based on the detector rate of the detector including the detector crystal and the determined sensitivity of the detector crystal, estimation of a mean random coincidence rate for each of a plurality of pairs of the detector crystals based on the singles rate of each detector crystal of each of the plurality of pairs of the detector crystals, correction of the acquired frame of positron emission tomography data based on the estimated mean random coincidence rates, and reconstruction of a positron emission tomography image based on the corrected frame of positron emission tomography data.

Determination of crystal singles rates to estimate mean random coincidence rate

A method for self-time alignment procedure for a PET scanner system is disclosed. Modeled time-of-flight (TOF) data are compared against the measured TOF data in order to find individual detector's time offsets (TOs). Then the TOs are estimated simultaneously by matching the TOF center of mass between the modeled and measured TOF data.

System and method for self-time alignment calibration for a positron emission tomography system

A method comprises: detecting a plurality of radiation events using a plurality of radiation detectors; determining a fraction of the plurality of radiation events, such that a coincidence circuit has sufficient capacity to process each radiation event in the fraction of the plurality of radiation events; counting the determined fraction of the plurality of radiation events using the coincidence circuit, and excluding a remainder of the plurality of radiation events from the counting; and performing positron emission tomography (PET) processing on each radiation event in the fraction of the plurality of radiation events.

Coincidence circuit with splitter

A method of scanner correction includes obtaining a first photopeak location for a first crystal in a detector. Image data is received from the first crystal. The first crystal generates the image data during a current imaging procedure. The image data is processed using the first photopeak location. A second photopeak location is determined for the first crystal from the image data. A difference between the first photopeak location and the second photopeak location of the first crystal is determined and the image data is reprocessed using the second photopeak location when the difference between the first photopeak location and the second photopeak location exceeds a predetermined threshold. An image is generated using the image data.

Data correcting using photopeak monitoring during imaging

A method for improving timing response in light-sharing scintillation detectors is disclosed. The method includes detecting an event, by a plurality of photo sensors, from a scintillation crystal. The method then includes sampling and digitizing the photo sensor outputs by an analog-to-digital converter. Then the method includes correcting associated timing data, by a processor, for each of the photo sensor outputs based on a lookup table. The method then includes selectively time shifting the photo sensor outputs based on the lookup table to generate corrected photo sensor outputs. The method then includes summing the corrected photo sensor outputs by the processor. The method then includes generating an event time, by the processor, for the detected event based on the sum of the corrected photo sensor outputs.

Timing response improvement in light-sharing detectors

A method, disclosure relates to for improving detection of true coincidence events and differentiating them from events detected from scattered and random gamma photons, comprises receiving electromagnetic radiation at a plurality of photo detectors that was generated by a scintillating crystal impacted by a gamma photon, and processing data received at a subset of the plurality of photo detectors that are closer to a scintillating crystal, thereby improving a timing coincidence window for detecting a coincidence event.

Use of crystal location in nuclear imaging apparatus to minimize timing degradation in a photodetector array

PET detector modules are provided within a multi-dimensional magnetic field, to confine the range of emitted positrons from an object being imaged to improve spatial resolution of reconstructed PET images. Each module includes a number of independent, optically isolated detectors. Each detector includes an array of scintillator crystals read out by an array of APDs (avalanche photodiodes).

PET imaging system with APD-based PET detectors and three-dimensional positron-confining magnetic field

A detector is provided for nuclear medicine imaging. Scintillator pixels form an axial array and a transaxial array. A first photosensor is positioned along the axial array; and a second photosensor is positioned along the transaxial array, wherein the first photosensor and the second photosensor provide dual event localization for nuclear medicine imaging.

Method and apparatus for providing depth-of-interaction detection using positron emission tomography (PET)

A depth of interaction-sensitive crystal scintillation detector features crystal types that alternate in three-dimensional checkerboard fashion, each type having a different crystal decay time. One or more photosensors are disposed on each of at least two orthogonal surfaces. The scintillation detector provides improved depth of interaction resolution. The different crystal types are identified by pulse shape discrimination processing.

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Knoxville, TN, United States of America

Mehmet Aykac