Systems and methods for reducing radiation dose in CT
AssigneeThe Regents of the University of California
InventorsDanny J J Wang, Thomas Martin, John M. Hoffman
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Abstract
A low-dose CT imaging system and method that operates according to a pulsed X-ray emission scheme according to a predefined sequence of rotation angles of the X-ray source, along with image reconstruction algorithms to achieve high spatial and temporal resolution for CT scans. The systems and methods involve high speed switching (on the order of milliseconds) to generate pulsed exposure of X-ray radiation to the patient, reducing radiation dose by 4-8 fold, or more.
Claims16
A system for reduced dose CT scanning of a subject, the system comprising:
- (a) a pulse generator configured to be coupled to an X-ray source of a CT scanner, the X-ray source being mounted on gantry so as to rotate within a cylindrical enclosure of the CT scanner;
- (b) said pulse generator configured to periodically switch off emission of X-rays from the X-ray source, using high speed electromagnetic switching on the order of milliseconds, into the cylindrical enclosure;
- and
- (c) a processor configured for controlling said pulse generator and receiving an output from said CT scanner;
- (d) a non-transitory memory storing instructions executable by the processor;
- (e) wherein said instructions, when executed by the processor, perform steps comprising:
- (i) controlling timing of the pulse generator so as to intermittently expose a subject to X-rays from the X-ray source at the pre-specified rotation angles of the gantry;
- (ii) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles of said X-ray source within the cylindrical enclosure of the CT scanner;
- (iii) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest.
An apparatus for reducing X-ray dose to a subject in a CT scanner, the CT scanner comprising an X-ray source being mounted on gantry so as to rotate within a cylindrical enclosure of the CT scanner, and a pulse generator coupled to the X-ray source to periodically switch off emission of X-rays from the X-ray source into the cylindrical enclosure, the apparatus comprising:
- (a) a computer processor coupled to the CT scanner and the pulse generator;
- and
- (b) a non-transitory computer-readable memory storing instructions executable by the computer processor;
- (c) wherein said instructions, when executed by the computer processor, perform steps comprising:
- (i) controlling timing of the pulse generator so as to intermittently expose a subject to X-rays from the X-ray source at pre-specified rotation angles of the gantry using high speed electromagnetic switching on the order of milliseconds;
- (ii) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles;
- and
- (iii) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest.
A reduced dose CT scanner for generating CT images of a subject, the CT scanner comprising:
- (a) an X-ray source disposed within a cylindrical enclosure, wherein the cylindrical enclosure comprising a plurality of detectors configured to detect X-rays emitted from the X-ray source, and in which the X-ray source is mounted on a gantry configured to rotate within the cylindrical enclosure of the CT scanner;
- (b) a pulse generator coupled to the X-ray source, wherein the pulse generator is configured to periodically switch off emission of X-rays from the X-ray source using high speed electromagnetic switching on the order of milliseconds into the cylindrical enclosure;
- and
- (c) a computer processor or server coupled to the pulse generator and the plurality of detectors for receiving pulsed images corresponding to exposures at pre-specified rotation angles of the X-ray source within the cylindrical enclosure;
- (d) a non-transitory memory storing instructions executable by the processor;
- (e) wherein said instructions, when executed by the computer processor or server, perform steps comprising:
- (i) timing of the pulse generator which is configured to intermittently expose a subject to X-rays from the X-ray source at pre-specified rotation angles of the gantry;
- (ii) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles;
- (iii) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest.
A method for reducing X-ray dose upon a subject in a CT scanner, the CT scanner comprising an X-ray source mounted on gantry so as to rotate within a cylindrical enclosure of the CT scanner and emit of X-rays into the cylindrical enclosure, the method comprising:
- (a) intermittently exposing a subject within the enclosure to X-rays from the X-ray source using high speed electromagnetic switching on the order of milliseconds at pre-specified rotation angles of the gantry;
- (b) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles;
- and
- (c) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest.
Dependencies are inferred from the claim text.