Abstract: A positron emission tomography (PET) scanner, including a first detector portion arranged circumferentially around a patient pallet, the first detector portion having a predetermined axial extent and transaxially subtending less than 360 degrees with respect to a central axis of the scanner defined by the first detector portion, wherein the first detector portion includes a plurality of first detector elements; and a second detector portion arranged separately from and opposing the first detector section, the second detector portion including a plurality of second detector elements, the second detector elements being of a different type than the first detector elements, wherein each of the first detector elements includes photomultiplier tubes (PMTs); and each of the second detector elements includes photosensors of a different type from the PMTs of the first detector elements.

Abstract: A positron emission tomography (PET) scanner, including a first detector portion arranged circumferentially around a patient pallet, the first detector portion having a predetermined axial extent and transaxially subtending more than 180 degrees, but less than 360 degrees with respect to a central axis of the scanner defined by the first detector portion; and a second detector portion arranged separately from and opposing the first detector section, the second detector portion having a radius of curvature smaller than a radius of curvature of the first detector portion, wherein the second detector portion transaxially subtends less than 180 degrees with respect to the central axis of the scanner.

Abstract: A triple-sensor motion detector is provided for illuminating the approach to a display case or other object. The triple-sensor motion detector provides a field of detection that spans the front width of the case, yet does not include the areas along the sides of the case. The detector reduces inadvertent triggering of the illumination by persons approaching the side of the case or approaching another case on the other side of an aisle.

Abstract: A method of imaging a region of interest (ROI) in an object, the ROI having an axial extent greater than an axial FOV of a PET scanner. The method includes determining a number of overlapping scans of the PET scanner necessary to image at least the axial extent of the ROI, wherein each scan has a same axial length equal to the axial FOV, and each scan overlaps an adjacent scan by a predetermined overlap percentage of the axial length of each scan. Further, the method includes determining a total amount of excess scanning length of the scans based on the number, the axial extent of the ROI, and the axial FOV, and determining a new overlap percentage based on the total amount of excess scanning length and the predetermined overlap percentage, so that a new total amount of excess scanning length, as determined with the new overlap percentage, is zero.

Abstract: A variable delay device is connected to a photosensor of a time-of-flight gamma ray detection system and includes a substrate on which a plurality of conductive pins are affixed. A first terminal connected to a first of the plurality of pins and a second terminal connected to the second of the plurality of pins are also affixed to the substrate. A jumper electrically connects the plurality of pins at a predetermined distance relative to the substrate, and a time delay of the variable delay device is determined based on the electrical path between the first and second terminals formed by the plurality of pins and the jumper.

Abstract: A gamma ray detector module that includes at least one crystal element arranged in a plane, a plurality of light sensors arranged to cover the at least one crystal element and to receive light emitted from the at least one crystal element, and a light guide arranged between the at least one crystal element and the light sensors, the light guide being optically connected to the at least one crystal element. Further, the light guide includes a narrow portion that positions at least one light sensor of the plurality of light sensors closer to the at least one crystal element than other light sensors of the plurality of light sensors. In addition, the light guide may include an angled recessed portion that positions another light sensor at an oblique tilt angle with respect to the plane of the at least one crystal element.

Abstract: A gamma ray detection system includes a plurality of detector modules having a same length, where each detector module is configured to detect gamma rays generated from positron annihilation events. A first detector module of the plurality of detector modules is shifted by a predetermined distance in an axial direction from a second detector module of the plurality of detector modules that is adjacent to the first detector module, where the predetermined distance is less than the length of the detector modules.

Abstract: A variable delay device is connected to a photosensor of a time-of-flight gamma ray detection system and includes a substrate on which a plurality of conductive pins are affixed. A first terminal connected to a first of the plurality of pins and a second terminal connected to the second of the plurality of pins are also affixed to the substrate. A jumper electrically connects the plurality of pins at a predetermined distance relative to the substrate, and a time delay of the variable delay device is determined based on the electrical path between the first and second terminals formed by the plurality of pins and the jumper.

Abstract: A positron emission tomography scanner system that includes detector modules arranged adjacent to one another to form a cylindrical detector ring. Each of the detector modules includes an array of scintillation crystal elements, a plurality of photosensors arranged to cover the array of crystal elements and configured to receive light emitted from the array of crystal elements, and a fiber optics plate arranged between the array of scintillation crystal elements and the plurality of photosensors, the fiber optics plate including a plurality of fibers configured to guide the light emitted from the scintillation crystal to the plurality of photosensors.

Abstract: A PET imaging system includes a measurement subsystem, a data acquisition subsystem, and a reconstruction subsystem. The measurement subsystem detects deflection in a patient pallet, and generates deflection information based on the detected deflection. The data acquisition subsystem receives the deflection information from the measurement subsystem and PET measurement data corresponding to a plurality of coincidence events from a PET scanner, and communicates the received deflection information and PET measurement data to the reconstruction subsystem. The reconstruction subsystem includes a processor that reconstructs a PET scan image using the deflection information and the PET measurement data communicated by the data acquisition subsystem.

Abstract: A method for reconstructing list mode data comprises: reconstructing all list mode data of a list mode data set (30, 160) to generate a first reconstructed image (32, 62); selecting a sub-set of the list mode data set; and reconstructing the sub-set of the list mode data set to generate an enhanced reconstructed image (84, 86). An image generation system comprises: a reconstruction module (24) configured to perform a standard reconstruction of a list mode data set to generate a standard reconstructed image (32, 62); and a re-reconstruction module (24, 70, 80, 82, 150, 152, 154) configured to perform a reconstruction other than the standard reconstruction of at least a portion of the list mode data set to generate an enhanced reconstructed image (84, 86).

Abstract: A positron emission tomography detector module that includes an array of optically isolated crystal elements and photomultiplier tubes that receive light emitted from the array of crystal elements and are arranged to cover the array of crystal elements. The photomultiplier tubes include photomultiplier tubes having two different sizes arranged in various patterns that minimize the number of edges. The axial extent of each detector module is at least three times longer than the other axis of the detector module.

Abstract: A method of processing positron emission tomography (PET) information obtained from a PET detector having a plurality of detector regions, each detector region having at least one detector module and a corresponding regional collector, the method including the steps of receiving PET event information for a single PET event, the PET event information including energy information and crystal position information of the single PET event; receiving non-detector event information; generating an event list that includes (1) a PET event entry, the PET event entry including a fine time stamp, the energy information, and the crystal position information, and (2) a non-detector event entry that includes the received non-detector event information; and transmitting the generated event list to a computer for off-line processing.

Abstract: An apparatus and associated method for gamma ray detection that improves the timing resolution is provided. A crystal of interaction in a scintillation crystal array emits scintillation light in response to interaction with a gamma ray. The scintillation light is detected by one or more photomultiplier tubes. Each photomultiplier tube that detects the scintillation light detects the light at a different time. The apparatus determines the location of the gamma ray interaction and uses the location of the interaction to generate correction times for each waveform generated by the photomultiplier tubes. The waveforms are corrected with the correction timings and combined to extract a time of arrival estimate for the gamma ray. Noise thresholding is also used to select waveforms having low noise for combination to extract the time of arrival estimate.

Abstract: A method and system for use in positron emission tomography, wherein a first processor element (234) is configured to reconstruct a plurality of positron annihilation events detected during a positron emission tomography scan using a list-based reconstruction technique to generate first volumetric data. A second reconstructor (226) is configured to reconstruct the plurality of events using a second reconstruction technique to generate second volumetric data for determining an error correction (228), the error correction applied to the first volumetric data to generate corrected volumetric data for generating a human-readable image (234). In one embodiment a multiplicative error correction is performed on the plurality of events, the first processor element (234) reconstructing the corrected plurality of events; and the second volumetric data error correction comprises an additive error correction.

Abstract: An imaging system comprises: a ring of positron emission tomography (PET) detectors; a PET housing at least partially surrounding the ring of PET detectors and defining a patient aperture of at least 80 cm; a coincidence detection processor or circuitry configured to identify substantially simultaneous 511 keV radiation detection events corresponding to electron-positron annihilation events; and a PET reconstruction processor configured to reconstruct into a PET image the identified substantially simultaneous 511 keV radiation detection events based on lines of response defined by the substantially simultaneous 511 keV radiation detection events.

Abstract: An imaging system (10) comprises a data device (30), which controls radiation data acquisition from a subject positioned in an examination region (18) for an examination. A rebinning processor (40) bins the acquired data periodically into a histogram (42). A transform (70) transforms the histogram (42) into individual independent or uncorrelated components, each component including a signal content and a noise content. A stopping determining device (52) compares an aspect of at least one selected component to a predetermined threshold (TH) and, based on the comparison, terminates the data acquisition.

Abstract: When employing hygroscopic scintillation crystals (32) in a nuclear detector (e.g., PET or SPECT), Silicon photo-multiplier (SiPM) sensors (34) are coupled to each scintillation crystal (32) to improve scintillation event detection and reduce scatter. The crystals (32) and sensors (34) are hermetically sealed in a detector housing (50) using a sealant layer (51). Electrical contacts (60) from each sensor (34) extend through the sealant layer (51) or are bused together such that the bus extends through the sealant layer (51). In this manner, hygroscopic scintillation crystals (e.g., LaBr, NaI, etc.) are protected from humidity and light scatter is reduced by direct coupling of the sensors (34) and crystals (32).

Abstract: When correcting attenuation in a nuclear image (e.g., PET or SPECT), an MR-based attenuation correction (AC) map (16) is generated using MR image data (14) of a subject (60). The subject (60) is then placed in a nuclear imaging device with a radioactive point or line source (18, 18?) from which transmission data is measured as the patient is imaged. In order to resolve ambiguity between air voxels and bone voxels in the MR-based AC map (16), estimated transmission data (24) is generated from the AC map and compared to the measured trans-mission data (22) from the point or line source. An error is iteratively calculated for the estimated and measured transmission data, and attenuation values of the AC map (16) are refined to minimize the error. The refined AC map (32) is used to correct attenuation in collected nuclear data (41) which is reconstructed into an attenuation corrected image (99) of the patient.

Abstract: An apparatus and associated method for gamma ray detection that improves the timing resolution is provided. A crystal of interaction in a scintillation crystal array emits scintillation light in response to interaction with a gamma ray. The scintillation light is detected by one or more photomultiplier tubes. Each photomultiplier tube that detects the scintillation light detects the light at a different time. The apparatus determines the location of the gamma ray interaction and uses the location of the interaction to generate correction times for each waveform generated by the photomultiplier tubes. The waveforms are corrected with the correction timings and combined to extract a time of arrival estimate for the gamma ray. Noise thresholding is also used to select waveforms having low noise for combination to extract the time of arrival estimate.