American Society for Nondestructive Testing (ASNT) Radiographic Testing Practice Test

The formula used to determine permissible accumulated personnel dose is based on the principle that the limits are dependent on the age of the individual, represented by "N." The formula incorporates a factor that increases the allowable dose as the individual's age increases, recognizing that individuals who are older may have had more time for radiation exposure and therefore may be allowed a slightly higher cumulative dose.

The specific formula, 5 (N - 18), indicates that for every year over the age of 18, the individual is permitted an accumulated dose of 5 millisieverts. This approach gives a clear guideline for exposure limits in order to maintain safety and minimize health risks associated with radiation. The structure of this formula emphasizes protection, as it ensures that younger individuals, who are generally more sensitive to radiation due to their longer life expectancy ahead, have stricter dose limits compared to older individuals.

This method of calculating permissible accumulated dose is commonly adopted in radiation safety protocols and aligns with the recommendations of various radiation protection agencies, thereby ensuring that safety standards are maintained in environments where personnel are potentially exposed to radiation.