Flat-panel CT machine

Abstract

The invention provides a flat-panel CT machine, which comprises a ray emitter and a flat-panel detector and adopts 360-degree scanning or 180-degree scanning. The length and width of a flat-panel detector are larger than those of a DSA flat-panel detector, the flat-panel detector can cover a single part of a human body, and spiral scanning is not needed any more. The scanning time is greatly shortened, and motion artifacts can be effectively reduced; the irradiation dose of a patient is greatly reduced; the spatial resolution and the number of longitudinal scanning layers are greatly improved,and gapless scanning is achieved. An X-ray emission pulse control technology is adopted, so that data obtained by the CT machine is complete and free of loss, and images are clearer. The scanning frequency is reduced by half through a pulse control technology or a 180-degree scanning mode; the requirement on the mobility of a thin film transistor of the detector can be reduced by about 10 times by a pulse control technology; the frequency is further reduced by redesigning the array element number of the detector, and the inversion frequency of a ray emitter is controlled within an achievablerange, so that the CT machine has the possibility of practical application.

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; however, if it is to be applied to a flat-panel CT machine, the size is still too small to include the abdomen and chest in the lateral direction; when the current flat-panel detector is applied to a CT machine, the scanning frequency and thin-film transistor The mobility requirements are too high, but in reality the frequency of flat panel detectors and the mobility of thin film transistors are generally too low to meet the requirements of CT machines

The above problems have not been solved so far. Except for CBCT, there is no flat-panel CT machine suitable for whole body scanning in the market.

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