Toshiba Medical Systems Corporation

Kabushiki Kaisha Toshiba

University of California

Hongwei Ye

Wenli Wang

Jian Zhou

Jinyi Qi

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.

Image-based point-spread-function modelling in time-of-flight positron-emission-tomography iterative list-mode reconstruction

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.

Method and system of random-event-based count-rate adaptive normalization for PET detector efficiency

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.

Cylinder source software-positioning method for PET calibration and image quality assurance

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.

Method and apparatus for estimating scatter in a positron emission tomography scan at multiple bed positions

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.

Method and device for calculating voxels defining a tube-of-response using a central-ray-filling algorithm

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.

Growing community of inventors

Kenosha, WI, United States of America

Hongwei Ye