Siemens Medical Solutions Usa, Inc.

Cti Pet Systems, Inc.

Maurizio Conti

Michael E Casey

Christian J Michel

Ronald Grazioso

A Andrew Carey

Larry Byars

Vladimir Y Panin

Peter Carl Cohen

James J Hamill

Piotr Szupryczynski

Mu Chen

Michel Defrise

Apparatuses, computer-readable mediums, and methods are provided. In one embodiment, a positron emission tomography ('PET') detector array is provided which includes a plurality of crystal elements arranged in a two-dimensional checkerboard configuration. In addition, there are empty spaces in the checkerboard configuration. In various embodiments, the empty spaces are filled with passive shielding, transmission source assemblies, biopsy instruments, surgical instruments, and/or electromagnetic sensors. In various embodiments, the crystal elements and the transmission source assemblies simultaneously perform emission/transmission acquisitions.

PET scanner with emission and transmission structures in a checkerboard configuration

Determining the position of a radioactive source in a PET system. Detecting a scatter coincidence event characterized by a full-energy photon detected at a first detector and partial-energy photon at a second detector. Measuring the arrival time difference between the partial energy photon and the full energy photon. Measuring the energy of the partial-energy photon. Determining a scattering point as a function of the position of the first detector, the position of the second detector, the energy of the partial-energy photon, the energy of an unscattered photon, the mass of a scattering electron, and the speed of light. Determining the position of a radioactive PET source along a line between the scatter point and the first detector as a function of the distance between scatter point and the first detector, the distance between scatter point and the second detector, and the measured time difference.

Positron emission tomography (PET) imaging using scattered and unscattered photons

A method for processing an image which has the steps of a) receiving acquired data necessary to obtain an image and estimating a preliminary image; b) selecting at least one image element within the image; c) performing an iterative algorithm for processing the image at least on the at least one image element; d) computing a difference between the processed at least one image element and the at least one image element; and e) repeating the steps c) and d) until the difference is below a predefined threshold.

Iterative image processing

For patient transmission data acquired simultaneously with patient emission data, blank transmission data are acquired in the absence of the patient emission and therefore under count rate conditions different from the count rate conditions of the patient transmission data. To prevent the different count rate conditions from causing artifacts in reconstructed tomographic images, a correction is made for spatially varying count rate effects on the attenuation correction. For example, the blank scan data are adjusted according to the count rate at which the patient emission data are acquired, and the adjusted blank scan data and the patient transmission data are used for attenuation correction of the patient emission data used for reconstructing a tomographic image.

Attenuation correction for nuclear medical imaging scanners with simultaneous transmission and emission acquisition

Fast reconstruction methods are provided for 3D time-of-flight (TOF) positron emission tomography (PET), based on 2D data re-binning. Starting from pre-corrected 3D TOF data, a re-binning algorithm estimates for each transaxial slice the 2D TOF sinogram. The re-binned sinograms can then be reconstructed using any algorithm for 2D TOF reconstruction. A TOF-FORE (Fourier re-binning of TOF data) algorithm is provided as an approximate re-binning algorithm obtained by extending the Fourier re-binning method for non-TOF data. In addition, two partial differential equations are identified that must be satisfied by consistent 3D TOF data, and are used to derive exact re-binning algorithms and to characterize the degree of the approximation in TOF-FORE. Numerical simulations demonstrate that TOF-FORE is more accurate than two different TOF extensions of the single-slice re-binning method, and suggest that TOF-FORE will be a valuable tool for practical TOF PET in the range of axial apertures and time resolutions typical of current scanners.

Fourier re-binning of time-of-flight positron emission tomography data

A method for acquiring PET images with reduced time coincidence window limits includes obtaining a preliminary image of a patient within a radiation field of view (FOV), determining the spatial location of the patient within the FOV based on the preliminary image, calculating a different time coincidence window based on the spatial location of the patient for each possible pair of oppositely disposed detectors, scanning the patient with a PET scanning system to detect a pair of gamma photons produced by an annihilation event, determining whether the detection of the pair of gamma photons occurs within the time coincidence window, accepting the detected event only if the detection of the gamma photons occurs within the time coincidence window, calculating the spatial location of accepted annihilation event, and adding the calculated spatial location of the annihilation event to a stored distribution of calculated annihilation event spatial locations representing the distribution of radioactivity in the patient.

Method for reducing an electronic time coincidence window in positron emission tomography

A normalization apparatus and method for a PET scanner with panel detectors for obtaining an estimate of a normalization array, for correction for count rate effects on the normalization array, and for measurement of the relation between the normalization array and the count rate. The method of the present invention is based on two quasi-independent radial and axial components, which are count rate dependent due to sensitivity changes across the detector blocks. A scatter source is disposed at the center of the FOV and a scatter-free source is disposed at the outer edge of the FOV. The method computes the normalization array through several steps which evaluate the geometric profile, the axial profile, and the correction factor. A count rate correction is introduced to extend the normalization array to any count rate.

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Knoxville, TN, United States of America

Maurizio Conti