Since 1895, X-ray diagnosis and treatment technology has developed rapidly, and the main progress can be divided into the following stages:
(1) Ion X-ray tube stage (1895~1912)
This is the early stage of X-ray equipment. At that time, the structure of the X-ray machine was very simple. It used a low-efficiency gas-containing cold cathode ion X-ray tube, used a bulky induction coil to generate high voltage, exposed high-voltage parts, and did not have precise control devices. The X-ray machine has small capacity, low efficiency, weak penetrating power, poor image clarity, and lack of protection. According to data records, an X-ray pelvic image was taken at that time and it took as long as 40 to 60 minutes of exposure time. The result was a photo. After being successful, the subject’s skin was burned by X-rays.
(2) Electronic X-ray tube stage (1913~1928)
With the development of electromagnetics, high vacuum technology and other disciplines, in 1910, American physicist W.D. Coolidge published a report on the successful manufacture of tungsten filament X-ray tubes. Actually used in 1913, its biggest feature is that the tungsten filament is heated to an incandescent state to provide the electrons needed for the tube current, so the tube current can be controlled by adjusting the heating temperature of the filament, so that the tube voltage and tube current can be adjusted independently , And this is exactly what is needed to improve image quality.
The invention of the grid in 1913 partially eliminated scattered rays and improved the quality of images. In 1914, a cadmium tungstate phosphor screen was made, and the application of X-ray fluoroscopy began. The dual focus X-ray tube was invented in 1923, which solved the needs of X-ray photography. The power of the X-ray tube can reach several kilowatts, the side length of the rectangular focal point is only a few millimeters, and the X-ray image quality is greatly improved. At the same time, the gradual application of contrast agents has continuously expanded the scope of X-ray diagnosis. It is no longer a simple tool for simply taking images of bones, but it has become a good tool for the gastrointestinal tract, bronchus, blood vessels, ventricles, kidneys, bladder, etc. in human tissues and organs with poor natural contrast (small difference in X-ray absorption). Important medical diagnosis facility that can be checked. At the same time, X-rays have also begun to be used in treatment.
