Abstract: A method and apparatus for reducing random events in positron emission tomography (PET) list mode data, the method including the steps of obtaining, for a PET scanner having a given reconstruction field of view (FOV), time-of-flight (TOF) prompt list-mode count data that includes TOF information, the TOF prompt list-mode count data including a plurality of entries; and filtering the obtained prompt list-mode count data by removing those entries in the obtained prompt list-mode count data that represent emission points lying outside a tangential TOF mask to obtain filtered list-mode count data.

Abstract: A method is provided for estimating scatter in a positron emission tomography (PET) scan at multiple bed positions, the method comprising calculating a first scatter sinogram based on scatter data obtained at a first bed position, calculating a second scatter sinogram based on scatter data obtained at a second bed position, and deriving a third scatter sinogram for a third bed position between the first bed position and the second bed position, wherein the third scatter sinogram is derived from the first scatter sinogram according to a first percentage of overlap of the first bed position with the third bed position, and from the second scatter sinogram according to a second percentage of overlap of the second bed position with the third bed position.

Abstract: A method of processing, by a processor of a computer, positron emission tomography (PET) information obtained from a PET detector, including the steps of obtaining a singles event list that includes a plurality of single event entries, each entry corresponding to a single event detected by the PET detector and including a timestamp, energy information, and crystal position information; and determining, based on the timestamp and the crystal position information of each entry and a predetermined coincidence time period, all event pairs within the plurality of single event entries, each event pair consisting of two single events whose respective timestamps differ by less than the predetermined coincidence time period, wherein the determining step determines that an event pair exists when at least two, but no more than k, single events are found within a given time window, wherein k is an integer value greater than or equal to two.

Abstract: A method is provided for estimating scatter in a positron emission tomography (PET) scan at multiple bed positions, the method comprising calculating a first scatter sinogram based on scatter data obtained at a first bed position, calculating a second scatter sinogram based on scatter data obtained at a second bed position, and deriving a third scatter sinogram for a third bed position between the first bed position and the second bed position, wherein the third scatter sinogram is derived from the first scatter sinogram according to a first percentage of overlap of the first bed position with the third bed position, and from the second scatter sinogram according to a second percentage of overlap of the second bed position with the third bed position

Abstract: A method of estimating random events in positron emission tomography list mode data, including obtaining time-of-flight (TOF) list mode count data that includes TOF information; converting the obtained TOF list mode count data into four-dimensional (4D) raw sinogram count data, without using the TOF information, wherein the 4D raw sinogram count data includes random count values; interpolating the 4D raw sinogram count data to generate 4D interpolated sinogram count data; low-pass filtering the 4D interpolated sinogram count data to remove noise; converting the low-pass filtered 4D interpolated sinogram count data into filtered 4D raw sinogram count data; and generating, by a processor, five-dimensional (5D) TOF raw sinogram count data from the filtered 4D raw sinogram count data by effectively applying a TOF mask filter to the filtered 4D raw sinogram count data.

Abstract: An apparatus and method for simulating a radiation phantom so as to calibrate or measure performance of a gamma detection system. The apparatus includes a line bar configured to rotate around an axis of rotation, a source carriage configured to move linearly along the line bar and to hold an attached radiation source, and a fixture assembly configured to support the line bar, the fixture assembly being configured to attach to a patient bed.

Abstract: A method of calculating a system matrix for time-of-flight (TOF) list-mode reconstruction of positron-emission tomography (PET) images, the method including determining a TOF geometric projection matrix G including effects of object attenuation; estimating an image-blurring matrix R in image space; obtaining a diagonal matrix D that includes TOF-based normalization factor; and calculating the system matrix H as H=DGR.

Abstract: A method and system for determining a position of a source including obtaining prompt data and related delayed data from a Positron Emission Tomography (PET) scanner, generating a sinogram from the prompt data, generating crystal efficiency correction factors by performing a normalization calibration based on the obtained delayed data, performing normalization correction on the generated sinogram based on the crystal efficiency correction factors to generate a corrected sinogram, rebinning the corrected sinogram to generate a plurality of two-dimensional sinogram slices, and determining a central axis for each of the plurality of two-dimensional sinogram slices using a center estimation process.

Abstract: A method and apparatus for generating crystal efficiency correction factors by performing a normalization calibration based on delayed data. The method and apparatus obtain delayed data from a scan of a patient using a Positron Emission Tomography (PET) scanner, generate a sinogram from the obtained delayed data, determine, using a processing circuit, mean fan and block line of response sensitivities from the generated sinogram, determine, using the processing circuit, mean detector efficiency based on the determined mean fan and block line of response sensitivities, determine, using the processing circuit, an individual crystal efficiency based on the determined mean fan and block line of response sensitivities and the mean detector efficiency for each module, and calculate the crystal efficiency correction factors based on the determined individual crystal efficiency of each module.

Abstract: A method and apparatus for smoothing random event data obtained from a Positron Emission Tomography (PET) scanner. The method includes obtaining initial random event data u(s, ?, t=0)=u0(s, ?), corresponding to t=0, calculating second-order central differences uss, u?? with respect to s, ?, calculating a gradient ut, using ut=2(uss+u??)??(u?u0), where ? is a constant parameter, and updating the random event data using u(s, ?, t2)=u(s, ?, t1)+?t ut, where ?t=t2?t1, t1=0 in a first iteration, and ?t is greater than 0. The method repeats the steps of calculating the second-order central differences, calculating the gradient, and updating the random event data until a change in u(s, ?, t) from a previous iteration is less than a predetermined threshold value.

Abstract: A method and apparatus for determining a coincidence window for imaging a region of interest of an object using a Positron Emission Tomography (PET) scanner. The method includes determining a diameter of a transverse field of view (FOV) for imaging the region of interest of the object; and calculating the coincidence window based on the determined diameter, a ring diameter of the PET scanner, an axial length of the PET scanner, and a time-of-flight resolution of the PET scanner.

Abstract: A method and device for calculating voxels defining a tube-of-response (TOR) within a reconstruction space of a Positron Emission Tomography (PET) apparatus having a plurality of crystals, the voxels within the reconstruction space having a predetermined size. The method includes selecting a center on each of two crystals defining a line of response, determining intersected voxels within the reconstruction space that intersect a straight line connecting the centers of the two crystals, calculating neighboring voxels of the intersected voxels, based on an expansion direction and an expansion distance, merging the intersected voxels and the neighboring voxels to form a merged set of voxels, and deleting duplicate voxels in the merged set of voxels to generate the voxels defining the TOR.

Abstract: A dust collection device for a sanding tool includes a bag having a sidewall with an inner surface and a coupler attached to the bag. The sidewall comprises at least one filter layer and an outer support layer. A sleeve having an outer surface, a sleeve sidewall, a first end, a second end, and at least one gap at either the first end or the second end is positioned within the bag. The sleeve's first end is positioned adjacent the coupler to direct incoming air towards the sleeve and the sleeve is positioned within the bag such that a bypass volume is present between the outer surface and the inner surface.

Abstract: A method, device, and system for calculating first and second distance ratios used to calculate a geometric probability between a voxel and a tube-of-response (TOR). The method includes determining a first-edge-line including a first-middle-point, determining a second-edge-line including a second-middle-point, determining a middle line of the TOR, projecting a first point of a first surface of the voxel to the middle line, projecting a second point of a second surface of the voxel to the middle line, calculating a first distance between one of the first and second middle-points and the first-projected-point, and a second distance between the one of the first and second middle-points and the second-projected-point, and determining a first distance ratio based on the first and second distances. The method calculates the second distance ratio similarly to the first distance ratio. The geometric probability is proportional to the product of the first and second distance ratios.

Abstract: An apparatus and method for simulating a radiation phantom so as to calibrate or measure performance of a gamma detection system. The apparatus includes a line bar configured to rotate around an axis of rotation, a source carriage configured to move linearly along the line bar and to hold an attached radiation source, and a fixture assembly configured to support the line bar, the fixture assembly being configured to attach to a patient bed.

Abstract: A method and apparatus for determining a coincidence window for imaging a region of interest of an object using a Positron Emission Tomography (PET) scanner. The method includes determining a diameter of a transverse field of view (FOV) for imaging the region of interest of the object; and calculating the coincidence window based on the determined diameter, a ring diameter of the PET scanner, an axial length of the PET scanner, and a time-of-flight resolution of the PET scanner.

Abstract: A method and apparatus for smoothing random event data obtained from a Positron Emission Tomography (PET) scanner. The method includes obtaining initial random event data u(s, ?, t=0)=u0(s, ?), corresponding to t=0, calculating second-order central differences uss, u?? with respect to s, ?, calculating a gradient ut, using ut=2(uss+u??)??(u?u0), where ? is a constant parameter, and updating the random event data using u(s, ?, t2)=u(s, ?, t1)+?t ut, where ?t=t2?t1, t1=0 in a first iteration, and ?t is greater than 0. The method repeats the steps of calculating the second-order central differences, calculating the gradient, and updating the random event data until a change in u(s, ?, t) from a previous iteration is less than a predetermined threshold value.

Abstract: A method and apparatus for reducing random events in positron emission tomography (PET) list mode data, the method including the steps of obtaining, for a PET scanner having a given reconstruction field of view (FOV), time-of-flight (TOF) prompt list-mode count data that includes TOF information, the TOF prompt list-mode count data including a plurality of entries; and filtering the obtained prompt list-mode count data by removing those entries in the obtained prompt list-mode count data that represent emission points lying outside a tangential TOF mask to obtain filtered list-mode count data.

Abstract: A method of estimating random events in positron emission tomography list mode data, including obtaining time-of-flight (TOF) list mode count data that includes TOF information; converting the obtained TOF list mode count data into four-dimensional (4D) raw sinogram count data, without using the TOF information, wherein the 4D raw sinogram count data includes random count values; interpolating the 4D raw sinogram count data to generate 4D interpolated sinogram count data; low-pass filtering the 4D interpolated sinogram count data to remove noise; converting the low-pass filtered 4D interpolated sinogram count data into filtered 4D raw sinogram count data; and generating, by a processor, five-dimensional (5D) TOF raw sinogram count data from the filtered 4D raw sinogram count data by effectively applying a TOF mask filter to the filtered 4D raw sinogram count data.

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.