What is CT?

The so-called CT refers to the computer X-ray tomography camera, which is a "hybrid" of X-ray and computer. At present, CT has developed to the fifth generation, and the time to scan an image has been shortened from 5 minutes to1100 seconds.

In fact, CT is developed on the basis of X-ray technology, but it does not directly photograph, but uses computer technology to process the light quantity information after X-ray scanning, and indirectly displays the cross-sectional image of internal tissue as a density image. It is more sensitive than X-ray detection technology 100 times.

Compared with X-ray examination, CT examination has many advantages: first, it is convenient for patients, and it does not need to inject contrast agent into the organ to be examined like X-ray examination, so it is not painful and dangerous to patients. Secondly, it can reflect the internal situation of organs, find early lesions, such as brain ct, find small tumors with a diameter of less than 0.5 cm, diagnose cerebral infarction, hydrocephalus, cerebral hemorrhage and cerebral artery malformation, and the accuracy rate of diagnosing brain tumors can reach about 94.8%; Whole-body CT can find metastatic tumors in the posterior wall of the heart with a diameter of 2 ~ 3 mm, and the accuracy rate of renal tumors can reach 94%. Thirdly, it is convenient to trace and review and help to judge diseases through the storage and video recording of electronic computers. At the same time, a large number of photographed images can be superimposed to form a stereoscopic image for stereoscopic and dynamic observation. CT has a strong ability to distinguish diseases. In particular, it can find lesions early and improve the cure rate.

With the progress of computer technology, CT technology is constantly developing and improving. If the spiral CT of three-dimensional image appears, the lesion can be located more accurately. There are also CT technologies using other physical energy sources, such as photon CT, ultrasonic CT, emission CT(ECT), microwave CT, positron CT, nuclear magnetic resonance CT(NMR) and so on. ECT and NMR are the main competitors of X-ray CT.