Medical X-ray is a medical test that uses X-rays to examine the inside of the human body, and is one of the earliest non-invasive tests used. X-rays are mainly used to detect lesions in bones, but are also useful for detecting lesions in soft tissues. x-rays are ionizing radiation, and therefore can be damaging to the human body.
X-rays were used in medical tests less than six months after their discovery in 1895, and the discoverer, Wilhelm Rontgen, was awarded the first Nobel Prize in Physics in 1901 for his discovery of X-rays.
Principle
X-rays are extremely short wavelength electromagnetic waves, whose wavelengths are shorter than ultraviolet rays, which are invisible to the naked eye, and therefore penetrate human tissues; in addition, X-rays can sensitize photographic negatives, and therefore can be used to record images of the human body under X-ray irradiation.
As X-rays pass through the human body, subject to different degrees of absorption, such as the amount of X-rays absorbed by the bone than the amount absorbed by the muscle, the amount of X-rays through the human body is not the same as the amount of X-rays, in the fluorescence screen or photographic film caused by fluorescence or photographic effect of the intensity of the role of the big difference, and thus in the fluorescence screen or photographic film (after the development of the film, the finalization of the) will show a different degree of shadow, reflecting the density distribution information of all parts of the body, and the human body. Reflects the information of the density distribution of the various parts of the human body. Based on the X-ray image, it is possible to determine the state of a certain part of the body's tissues, so X-ray diagnostic technology has become the world's first application of non-traumatic visceral examination technology.
Advantages and disadvantages
There are two types of X-ray examinations: fluoroscopy and photography.
The main advantages of fluoroscopy: the patient's position can be rotated to change the direction of observation; to understand the dynamic changes in the organs, such as the heart, large blood vessel pulsation, diaphragm movement and gastrointestinal peristalsis, etc.; fluoroscopy of the equipment is simple, easy to operate, less expensive, and can be immediately concluded, etc..
The main disadvantages of fluoroscopy: low brightness of the screen, poor contrast and clarity of the image, it is difficult to observe the density and thickness of the lesser difference between the organs and the density and thickness of the larger parts. For example, the skull, abdomen, spine, pelvis and other parts are not suitable for fluoroscopy. Can not leave an objective record, does not facilitate the review of lesions, comparison.
The main advantages of photography: clear imaging, contrast and clarity are better; can be used as an objective record, easy to review the comparison and consultation.
The main disadvantages of photography: each photo is only an orientation and an instantaneous X-ray image, in order to establish the concept of three-dimensional, often need to be perpendicular to each other two orientation photography, such as orthopantomograms and lateral position; the observation of the functional aspects of the less convenient than the fluoroscopy and direct; the cost of a little more than the fluoroscopy, but compared to other imaging tests, such as CT, magnetic **** vibration is relatively inexpensive.
The X-ray equipment is simpler than the MR*** vibration equipment, so generally players will receive X-ray examination first after the injury, and then through the MR*** vibration for further examination.
In addition, regardless of the type of test, X-rays have the potential to cause harm to the human body because the X-rays taken for X-rays are a form of ionizing radiation, which means that the X-rays pass through the body causing some of the body's molecules to ionize, which can cause harm to the human body.
Results
There are two types of X-ray test results:
If no discernible structural damage is found, the result is "negative";
If discernible damage is found, the result will state the location, type and extent of the damage. results.