X-ray CT image reconstruction method and X-ray CT system

An X-ray computed tomography (CT) image reconstruction method comprising:

• rotating a fan-shaped X-ray beam about a subject, the fan-shaped X-ray beam having a thickness with respect to an axis of the subject and irradiating the subject;
• acquiring fan-shaped beam data based on X-ray beams that are irradiated from each of a plurality of successive angles of rotation and attenuated by the subject;
• producing parallel-beam data based on the fan-shaped beam data that includes projection data taken at each angle of rotation of the fan-shaped X-ray beam;
• enhancement processing the parallel-beam data associated with respective projection data acquired along each of a plurality of projection lines of the fan-shaped X-ray beam to sharpen the parallel-beam data to create enhanced fan-shaped beam data;
• and
• reconstructing an image using the enhanced parallel-beam data such that a resolution of the image is maintained as a distance between respective points within the image and a scan center position increases.

An X-ray computed tomography (CT) image reconstruction method comprising:

• rotating a fan-shaped X-ray beam about a subject, the fan-shaped X-ray beam having a thickness with respect to an axis of the subject and irradiating the subject;
• acquiring fan-shaped beam data based on X-ray beams that are irradiated from each of a plurality of successive angles of rotation and attenuated by the subject;
• producing parallel-beam data based on the fan-shaped beam data that includes projection data taken at each angle of rotation of the fan-shaped X-ray beam;
• reconstructing a tomographic image of the subject using the parallel-beam data;
• identifying a scan center position equivalent to a center position of the tomographic image;
• and
• performing enhancement processing on pixels contained in the tomographic image associated with respective projection data acquired along each of a plurality projection lines of the fan-shaped X-ray beam to sharpen the tomographic image to enhance the fan-shaped beam data, wherein a degree of image sharpening increases as a distance from the scan center position increases.

An X-ray computed tomography (CT) system comprising:

• a rotator configured to rotate a fan-shaped X-ray beam about a subject, the fan-shaped X-ray beam having a thickness with respect to an axis of the subject and irradiating the subject;
• an X-ray detector configured to detect fan-shaped beam data based on X-ray beams that are irradiated from each of a plurality of successive angles of rotation and attenuated by the subject;
• an enhancement device configured to process respective projection data acquired along each of a plurality of projection lines of the fan-shaped X-ray beam to sharpen the projection data to create enhanced fan-shaped beam data;
• a projection line conversion device configured to produce parallel-beam data based on the enhanced fan-shaped beam data;
• and
• an image reconstruction device configured to reconstruct an image using the parallel-beam data such that a resolution of the image is maintained as a distance between respective points within the image and a scan center position increases.

An X-ray computed tomography (CT) system comprising:

• a rotator configured to rotate a fan-shaped X-ray beam about a subject, the fan-shaped X-ray beam having a thickness with respect to an axis of the subject and irradiating the subject;
• an X-ray detector configured to detect fan-shaped beam data based on X-ray beams that are irradiated from each of a plurality of successive angles of rotation and attenuated by the subject;
• a projection line conversion device configured to produce parallel-beam data based on the enhanced fan-shaped beam data;
• an enhancement device configured to enhance the parallel-beam data associated with respective projection data acquired along each of a plurality of projection lines of the fan-shaped X-ray beam to sharpen the parallel-beam data to create enhanced fan-shaped beam data;
• and
• an image reconstruction device configured to reconstruct an image using the enhanced parallel-beam data such that a resolution of the image is maintained as a distance between respective points within the image and a scan center position increases.

An X-ray computed tomography (CT) system comprising:

• a rotator configured to rotate a fan-shaped X-ray beam about a subject, the fan-shaped X-ray beam having a thickness with respect to a body axis of the subject and irradiating the subject;
• an X-ray detector configured to detect fan-shaped beam data based on X-ray beams that are irradiated from each of a plurality of successive angles of rotation and attenuated by the subject;
• a projection line conversion device configured to produce parallel-beam data based on the fan-shaped beam data;
• an image reconstruction device configured to reconstruct a tomographic image of the subject using the parallel-beam data;
• and
• an enhancement device configured to identify a scan center position that is equivalent to a center position of the tomographic image and to perform enhancement processing on pixels contained in the tomographic image associated with respective projection data acquired along each of a plurality of projection lines of the fan-shaped X-ray beam to sharpen the tomographic image to enhance the tomographic image, wherein a degree of image sharpening increases as a distance from the scan center position increases.