What Is Digital Radiography?

Automatic radiography ^[1] refers to the use of the nature of the different degrees of radiation absorption when the radiation penetrates the object, the radiation is projected on the film, after development to obtain photos showing changes in object thickness and internal defects. Automatic radiography mainly includes X-ray or gamma radiography. The entry introduces the development history, working principle, equipment composition and precautions of the two methods during implementation.

Autoradiography is a method that uses X-ray or gamma rays to detect materials and workpieces, and uses radiographic film as a recording medium and display method ^[2]

(1) X-rays and Y-rays have adverse effects on human health. The direct rays of radiation and the effects of scattered rays should be avoided as much as possible ^[2] .

(2) Dose supervision of radiographers should be carried out in accordance with Chapter 2 of GB 4792-1984.

(3) Personnel engaged in radiography should be provided with a dosimeter or other dose testing equipment to determine the amount of radiation exposure in the working environment and the cumulative dose received by an individual. In the gamma-ray inspection operation, the radiation dose near the workplace and the gamma-ray source container should be measured every time. In order to resolve the position of the radiation source, avoid accidental exposure.

(4) A safety line shall be provided when performing radiographic inspection at the inspection site. There should be obvious signs on the safety line, and red lights should be set at night. A warning sign should be set up on the passage where the inspection personnel can easily reach the safety line, indicating that radiography is in progress. Non-detection personnel should not enter the safety line, and write the radiation exposure on the safety line.

(5) According to the provisions of Chapter 3 of GB 4792-1984, the maximum dose equivalent that non-detection personnel are allowed to receive per year is 5 millisieverts (MSv) [that is, 0.5 rem (rem)]. Based on this, it is possible to calculate the time that non-detection personnel work or stay near the safety line.