The difference between CT and chest X-ray

Chest X-ray is the normal chest X-ray examination. The basic conditions for the formation of chest X-ray examination are that chest X-ray has certain penetrating power, and there are differences in density and thickness of tissue structure. The remaining X-ray forms X-ray imaging through the imaging process. Through the difference between X-ray imaging tissues with different densities, the method to reveal lung lesions is chest X-ray. Chest CT uses X-ray data to scan a layer of a certain thickness of the examination part of the human body. The detector receives the X-rays passing through the layer, converts them into visible light, converts them into electrical signals by a photoelectric converter, and then passes through an analog-to-digital converter. It is converted into a digital signal and input into a computer for processing. The image formation process divides the selected layer into a number of cuboids of the same volume, which is called body velocity. The information obtained from the scan is obtained through the computer. X-ray attenuation coefficient or absorption coefficient of each body velocity is arranged into a matrix, i.e. digital matrix. Each number in the digital matrix is converted into a small square with different gray levels from black to white, i.e. pixels, and arranged in matrix to form a CT image. The imaging principle of chest CT and chest radiography is very different, and their clinical application is also different.