Flat panel CT machine

Abstract

The invention relates to a scanner of a flat panel CT machine. The scanner comprises a frame, a rotating device, a ray emitter and a flat panel detector. The ray emitter and the flat panel detector are oppositely disposed in the rotating device and can be driven by the rotating device to conduct circular motion relative to the same axis synchronously and oppositely. A control circuit of the ray emitter is provided with a pulse modulating circuit, and the ray emission of the ray emitter is controlled by reading pulse signals of the flat panel detector. The reading frequency of the flat panel detector is variable, and ray emission pulse signals and the reading pulse signals of the flat panel detector are consistent in frequency but opposite in phase. The flat panel detector is applied to theCT machine to replace the existing CT detector. The flat panel detector can choose wider width, conducts gap-free scanning, and can ensure no detection missing. When the ray emitter emits rays, the flat panel detector only collects data without reading, and does not emit the rays during reading, trailing and afterglow are avoided, data obtained by the CT machine are more realistic, and images areclearer.

Description

technical field [0001] The invention relates to the 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 a digital / analog converter (digital / analog...

AI Technical Summary

Problems solved by technology

[0005] 1. The number of rows of detectors is limited, so that the scanning range that can be scanned in one rotation is relatively narrow (the widest detector in the vertical direction is 160mm, which can basically meet the requirements of single-turn scanning of small parts, but still cannot meet the requirements of single-turn scanning 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 helical scanning, the image scanned in one circle is not a real cross-section, but a cross-section image with a certain layer thickness that is not on the same section, 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 highest meaningful pixel is not high

[0009] 5. At present, the single-side size of medical flat-panel CT machines 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 flat-panel CT machines, the size is still too small. Abdomen and chest cannot be included in the scan

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