Flat panel CT (computed tomography) machine

Abstract

The invention provides a flat panel CT (computed tomography) machine. The flat panel CT machine comprises a ray emitter and a flat panel detector, wherein the ray emitter adopts 360-degree or 180-degree scanning; the length of the flat panel detector in the axial direction perpendicular to circular motion of the flat panel detector is larger than 17 inches. The flat panel detector has larger length and width than a flat panel detector for DSA, can cover single part of the human body and requires no helical scanning. A bed does not move during scanning, the scanning time is substantially reduced, and motion artifact can be effectively reduced; the irradiation dosage of patients can be substantially reduced; the spatial resolution and longitudinal scanning layer number are substantially increased, gapless scanning is realized, and missing examination can be ensured. An X-ray emission pulse control technology is adopted, trailing and afterglow are avoided, so that data obtained by the CT machine are more real, and images are clearer. By use of the pulse control technology or semi-circle scanning manner, the scanning frequency is halved, and the flat panel CT machine has the possibility of actual application by redesigning the element number of the detector.

Description

technical field [0001] The invention relates to the technical field of CT equipment, in particular to a flat-panel CT machine. Background technique [0002] CT (Computed Tomography), that is, computerized tomography. The basic principle of existing CT imaging is to use X-ray beams to scan a layer of a certain thickness of the human body inspection site. The X-rays that pass through this layer are received by the detector and converted into visible light. The analog / digital converter (analog / digital converter) converts the digital signal into a computer for processing. The processing of image formation is like dividing the selected layer into several cuboids with the same volume, which are called voxels. The scanned information is calculated to obtain the X-ray attenuation coefficient or absorption coefficient of each voxel, and then arranged into a matrix, that is, a digital matrix. Numerical matrices can be stored on disk or CD. Through the digital / analog converter, eac...

AI Technical Summary

Problems solved by technology

[0005] 1. The number of detector rows is limited, so that the scanning range of 360°rotational scanning is relatively narrow (now the widest vertical detector is 160mm, which can basically meet the single-turn scanning requirements of small parts, but still cannot meet the single-turn scanning requirements of large parts. circle scanning requirements), it takes multiple circles of helical scanning to complete a part, and the bed is moving during scanning, which is easy to form motion artifacts

[0006] 2. Because of the helical scanning, the scanned 360° image is not a real cross-sectional image, but a cross-sectional image with a certain layer thickness that is not on the same section plane, although the current 256 rows can already achieve a layer thickness of 625um (the thinnest 400um ), but it is not an isometric image after all; there is an interlayer gap, although the current 256 rows can also give a 625um (thinnest 400um) thick interlayer gap image through the algorithm, but it is not a real image after all

There is a possibility of missed detection of early very subtle lesions

[0007] 3. The scanning time is long; the radiation dose of the patient is also large

Due to the need for multiple scans, it takes a long time; it also leads to an increase in the dose of radiation exposure to the patient

[0008] 4. The spatial resolution is low, and the pixels of the reconstructed image are not high

However, the single-side size of the medical flat panel detectors used for DR and DSA on the market is up to 17 inches (about 43cm), which can fully meet the needs of use, but if it is to be applied to a flat-panel CT machine, the size is still too small to be used in the horizontal direction. The abdomen and chest are included in the scanning range; at the same time, the images obtained after trying are not ideal, and no effective solution has been found so far, so it cannot be promoted to the market

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