The working principle of the X-ray image intensifier (hereinafter referred to as the intensifier) is realized by using the physical electronic and optical principles. In simple terms, the image formed by the X-ray penetrating the illuminated object is projected to the image receiving end of the intensifier, thereby exciting the receiving end of the intensifier to generate a faint visible light image. The light generated by this image excites the photocathode to generate escaped electrons, which are accelerated and focused to the image output end of the intensifier under the action of a high-voltage electric field. Under the dual action of electrons and accelerated convergence, the phosphor screen at the image output end of the intensifier is excited to produce a visible light image with sufficient brightness. The brightness of the image generated by the output screen is enough to make the electronic camera photosensitive, thus realizing the conversion of X-ray signal-→visible light signal-→electrical signal. The electronic images converted into optical signals can be arbitrarily processed by the camera and transmitted to a farther place to be viewed by a monitor, which also realizes the isolation of man and machine and keeps the operator away from radiation. At the same time, due to the principle of electron acceleration excitation of the intensifier, the brightness of the image can be further enhanced, and the radiation dose of the subject can be greatly reduced, thus achieving the purpose of reducing radiation damage.
The system composed of X-ray image intensifier, camera and monitor is called X-ray intensifier TV system. The benefits of using the intensifier TV system for medical X-ray machines are obvious. First, the X-ray machine equipped with this system can easily operate in compartments, protect the operator from X-ray radiation damage and reduce inspections. Secondly, it can realize the operation in the dark room, get rid of the original dark room environment, improve the fear of patients and reduce the rate of misdiagnosis; thirdly, due to the inherent characteristics of TV signals, it can be easily recorded and saved, which is convenient for expert consultation. and teaching references.