When people see a doctor in a hospital, they usually take X-rays. What principle does this use?

When people see a doctor in a hospital, not all diseases need X-rays. Usually they need physical examination, respiratory system, bone and joint system and digestive system examination, which is also the main advantage of X-ray imaging.

As we all know, taking X-rays has radiation effect, so taking X-rays frequently is harmful to people's health, and it is a medical imaging examination that hospitals have to use. But why do we have to use X-rays? Instead of other tests, CT, ultrasound, MRI? Because X-ray examination of the following diseases has its own advantages, according to what I know, let's take a look at the principle of digital X-ray imaging:

First of all, according to the different means of X-ray examination, it can be divided into general examination and contrast examination: general examination is general fluoroscopy or contrast examination without introducing contrast agent. Contrast examination is the examination of introducing contrast agent into cavities, gaps, tubes and passages in human body; According to the different imaging methods, it can be divided into fluoroscopy and photographic examination: fluoroscopy is simple and easy to do, and it can know the pulsation of the great vessels of the heart, diaphragm movement, gastrointestinal peristalsis and so on. No posture check. However, fluoroscopy lacks permanent image records and the fluorescent screen is not bright enough, which is not suitable for parts with small or large differences in density and thickness of tissues and organs, such as skull and pelvis. Photographic inspection is the most commonly used inspection method at present. The changes of tissue thickness and density are permanently recorded in the photo, and the image is clean and has good contrast. But you can't do dynamic inspection. It plays a great role in the contour change, density change and function change of the disease.

X-ray examination has advantages and disadvantages. For ordinary families, the problem is not big. Hospitals generally recommend X-ray examination because it is enough to find problems. The most important thing is that the price is much cheaper than other exams. Of course, family conditions can also do CT, but there is still radiation. Non-radiation tests are ultrasound and nuclear magnetic resonance, which are expensive and should be carefully selected by ordinary families.