With the development of economy and society, China's radiation diagnosis and treatment is developing rapidly. Imaging examination needs to be exposed to radiation. The clinical effect of radiation therapy is getting better and better, and it is inseparable from the support of radiation! Therefore, the exposure dose received by staff and the public is also increasing.
In order to prevent and reduce the impact of ionizing radiation generated in the process of radiation diagnosis and treatment on radiation workers and related public health, the basic standard for ionizing radiation protection and safety of radiation sources (GB 18871-2012) gives dose limits for occupational exposure and public exposure of radiation workers: the effective dose of occupational exposure is 50 mSv / year in any year, The annual average effective dose determined by the audit department for five consecutive years (but no retrospective average) is 20 mSv / year.
The annual effective dose of public exposure is 1 mSv / year. Under special circumstances, if the average dose in five consecutive years does not exceed 1 mSv / year, the effective dose in a single year can be increased to 5 mSv / year.
Following the optimization principle of protection and safety, in order to make all kinds of exposure dose not only lower than the specified limit value, but also control it to the lowest level that can be reasonably achieved, the radiation health supervision department / medical institution has stipulated the management target value of exposure dose for professionals and the public.
According to the basic standard for ionizing radiation protection and safety of radiation sources (GB 18871-2012), 'the dose constraint value should generally be within the range of 10% ~ 30% (0.1 ~ 0.3msv / year) of the public dose limit', the radiation health regulatory department / medical institution stipulates that the public dose management target value is 0.25msv/year; According to the public dose constraint value in the basic standard for ionizing radiation protection and safety of radiation sources (GB 18871-2012), and referring to the annual investigation level of occupational exposure dose (5msv) in the code for personal monitoring of occupational external exposure (GBZ 128-2019), the radiation health supervision department / medical institution stipulates that the management target value of radiation workers is 5msv / year.
Regulatory departments and hospitals set management target values, which aims to establish and improve the radiation protection assurance system, strictly eliminate radiation accidents, and prevent the occurrence of general radiation accidents and more serious radiation accidents; The management target value is lower than the personal dose limit.