Dr. Tsubokura's Radiation Lecture Vol.134

Author: Masaharu Tsubokura PhD.

Editors: Akihiko Ozaki M.D.,PhD., Yuki Senoo

267. The importance of dose control for occupational exposure

An occupational exposure means that workers have received ionizing radiation during the performance of their duties. Occupational groups that are routinely exposed to radiation include coal miners, who usually work in areas of high natural radiation, airline crews, workers at nuclear power plants, physicians, nurses, and radiology technicians. While there is no dose limit for radiation exposure relating to medical examinations or treatments among patients, a law exists that prescribes regulatory dose limits for occupational radiation exposure so that workers can avoid receiving excessive exposure to radiation.

Generally, when people hear the term “occupational radiation exposure,” many think that it refers to radiation exposure among workers at nuclear power plants. Of course, control of radiation exposure is one of the most important work environment issues at nuclear power plants. However, it has been reported that nearly 90% of the total occupational exposure in the world is caused by naturally occurring radiative substances. Therefore, coal miners and cabin crews are at the highest risk of receiving high-dose radiation.

On the other hand, the rest of the total occupational exposure, or 10%, is caused by man-made radiation, and medical radiation exposure contributes to the majority of man-made occupational exposure—exposure received by healthcare professionals such as physicians, nurses, and radiology technicians when they are performing examinations or providing treatment using radiation.

In summary, it is crucial to control occupational radiation exposure not only for those working at nuclear power plants but also for other professionals at high risk of exposure.

268. Efforts to minimize occupational radiation exposure

Occupational exposure refers to ionizing radiation exposed during the performance of one’s duties. Occupational groups that are routinely exposed to radiation include coal miners, who are usually working in high-natural-radiation areas, airline crews, workers at nuclear power plants, physicians, nurses, and radiology technicians.

Exposure from manmade radiation accounts for approximately 10% of total occupational exposure, and the majority of it is caused by medical radiation exposure, which corresponds to radiation received from health care professionals, such as physicians, nurses, and radiology technicians when they are performing examinations and treatment using radiation.

According to previous evidence, radiation technicians tended to receive higher doses of radiation exposure than physicians and nurses did, and health care professionals working at general hospitals tended to receive higher doses of radiation exposure than those working at university hospitals or clinics did.

In any case, the overall average of annual radiation exposure among health care professionals usually did not exceed one millisievert. In contrast, the proportion of health care professionals with annual radiation exposure exceeding 20 millisieverts was highest among physicians (one in 2000). Of these physicians, some were reported to have received radiation exposure exceeding 50 millisieverts.

In addition, for furthering developing medical equipment, it is crucial to reduce occupational exposure by sharing knowledge as well as improving the work environment and protocols.

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The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, 1st and 8th of April 2020 was reproduced for MRIC Global under the author's permission.