What is the imaging principle of x-ray computed tomography (CT)?

CT is the abbreviation of Computed Tomongraphy, which is called Computed X-ray Tomography in Chinese. CT has become an indispensable means of non-invasive X-ray examination.

The basic principle of CT imaging is that X-ray beams are irradiated from multiple directions along the selected fault plane of a certain part of the human body, and some X-rays are absorbed by tissues and accepted by detectors, and the transmitted X-rays are measured. After digital comparison, the absorption coefficient of tissue per unit volume in this plane is calculated, and then the image is reconstructed.

Compared with conventional X-ray examination technology, CT examination technology has a high sensitivity of 100 times, especially for soft tissues with similar density. That is to say, the resolution of CT on tissue density is higher than that of X-ray, but the spatial resolution is generally not necessarily higher than that of X-ray imaging, so it can not completely replace X-ray examination at present. In addition, CT technology is developing towards high speed and simplification.