Abstract: A method for interpolating at least one oblique line of response ray representing nuclear image projection data through a rectangular volume and a system for using the method. The method consists of steps of interpolating all the direct rays in a rectangular volume, making a projected ray by projecting the oblique ray onto a surface of the rectangular volume, matching the projected ray to a coinciding interpolated direct ray, shearing the rectangular volume to match the projected ray, and interpolating the oblique ray in the sheared volume.

Abstract: Axial rebinning methods are provided for 3D time-of-flight (TOF) positron emission tomography (PET), based on 2D data rebinning. Rebinning is performed separately for each axial plane parallel to the axis of the PET scanner. An analytical approach is provided that is based on a consistency condition for TOF-PET data with a gaussian profile. A fully discrete approach is also provided, wherein each 2D TOF-PET data is calculated as a linear combination of 3D TOF-PET data having the same sinogram coordinates s and ?.

Abstract: A method of TOF-PET image reconstruction using time-truncated TOF-PET projection data. The time-truncated TOF-PET data is obtained by narrowing the scanner time window to a smaller “time window field of view,” which reduces the field of view of a TOF-PET scanner. This results in a lower list mode stream transfer rate, which can be useful in high count rate data acquisitions, in particular 82Rb cardiac studies.

Abstract: The present invention provides a method for estimating crystal efficiency in a PET detector that takes axial compression into account. It does so via an iterative methodology in which a ?-map is first generated and then is used to obtain a solution for the equation L ? ( ? i ) = ? n ? N ? ? y n ? log ? ? i , j ? span ? ? g ij ? ? i ? ? j ? x ij - ? i , j ? span ? ? g ij ? ? i ? ? j ? x ij , wherein gij is a geometric factor for LOR(i,j), ?i and ?j are the efficiencies for crystal i and crystal j, and xij is the line integral of the source distribution along LOR(i,j). Once efficiencies are determined, they are used to calibrate the PET detector.

Abstract: A method of TOF-PET image reconstruction using time-truncated TOF-PET projection data. The time-truncated TOF-PET data is obtained by narrowing the scanner time window to a smaller “time window field of view,” which reduces the field of view of a TOF-PET scanner. This results in a lower list mode stream transfer rate, which can be useful in high count rate data acquisitions, in particular 82Rb cardiac studies.

Abstract: 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.

Abstract: A method for interpolating at least one oblique line of response ray representing nuclear image projection data through a rectangular volume and a system for using the method. The method consists of steps of interpolating all the direct rays in a rectangular volume, making a projected ray by projecting the oblique ray onto a surface of the rectangular volume, matching the projected ray to a coinciding interpolated direct ray, shearing the rectangular volume to match the projected ray, and interpolating the oblique ray in the sheared volume.

Abstract: A method and system for reconstructing PET image data from a cylindrical PET scanner by incorporation of axial system response. The method includes the steps of: assuming the decomposition of axial components into individual line-of-response (LOR) contributions, approximating each LOR spreading in image space as depth-independent, implementing each LOR response, combining the LORs to produce large span projection data, implementing the back projector as a transposed matrix, and assembling the LOR projections and spans for each azimuthal angle.

Abstract: Axial rebinning methods are provided for 3D time-of-flight (TOF) positron emission tomography (PET), based on 2D data rebinning. Rebinning is performed separately for each axial plane parallel to the axis of the PET scanner. An analytical approach is provided that is based on a consistency condition for TOF-PET data with a gaussian profile. A fully discrete approach is also provided, wherein each 2D TOF-PET data is calculated as a linear combination of 3D TOF-PET data having the same sinogram coordinates s and ?.

Abstract: The apparatus and method include performing a medical image scan, including providing a contrast agent, performing a first scan at a first energy level, and performing a second scan at a second energy level, wherein radiation exposure to a patient of the first scan and the second is comparable to a single scan at a standard energy level.

Abstract: 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.