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What are the recommended annual dose limits for radiation exposure?
The ICRP and the National Council on Radiation Protection and Measurements (NCRP) provide guidelines regarding the health and safety aspects of ionizing radiation exposure relevant to patients and healthcare providers.
According to ICRP, 20 mSv/year averaged over 5 years (ie, a limit of 100 mSv in 5 years) is the maximum occupational effective dose, with no annual effective dosage exceeding 50 mSv/year. According to NCRP, the occupational dose limit is 50 mSv in any 1 year, and the lifetime limit is 10 mSv, multiplied by the individual’s age in years.
ICRP also defines effective dose limits related to certain body organs, ie, 150 mSv for the lens of the eye, 500 mSv for the skin (average dose over 1 cm of the most highly irradiated area of the skin), and 500 mSv for the hands and feet.
No dose limitation is recommended in any rescue operation (Procedures reducing mortality and morbidity) where the benefits of procedures outweigh the risks of occupational radiation exposure.
Otherwise, every effort should be made to minimize radiation exposure below 50% of the maximum annual occupational dosage limit.
Annual dose limits for radiation exposure are established by the NRC in the Code of Federal Regulations.
Radiation workers may not receive more than 50 mSv per year to the whole body or 500 mSv to an individual organ or to the skin. A lower annual limit of 150 mSv is prescribed for the lens of the eye, because of the increased risk of cataracts.
Annual limit on intake (ALI) – the derived limit for the amount of radioactive material taken into the body of an adult worker by inhalation or ingestion in a year.
Radiation workers are required to wear thermoluminescent dosimeters (typically embedded within badges or rings) so that their exposure can be monitored.
Radiation workers who exceed annual limits will be prevented from continuing in their occupations for the rest of the year if they exceed the annual limit.
Members of the general public are limited to 1 mSv per year. In the United States, this does not apply to individuals who are exposed to ionizing radiation from medical imaging, and at present there are no limits on the annual exposure of an individual patient.
However, many European countries have established diagnostic reference levels (DRLs), which provide recommended limits on radiation dose indices for diagnostic and interventional radiology examinations as well as nuclear medicine studies.
ALI is the smaller value of intake of a given radionuclide in a year by the “reference man” that would result in a committed effective dose equivalent of 0.05 Sv (5 rem) or a committed dose equivalent of 0.5 Sv (50 rem) to any individual organ or tissue.
Stanford Health Physics also ensures that radiation exposure to members of the public and non-occupational workers do not exceed regulated dose limits.
The dose limit to non-occupational workers and members of the public are set at two percent of the annual occupational dose limit.
Therefore, exposure to a non-radiation worker must not exceed 100 mrem/year. This exposure would be in addition to the annual background radiation.
The recommended annual dose limits for radiation exposure vary depending on the type of radiation and the specific circumstances. These limits are set by international organizations and regulatory bodies to ensure that exposure to radiation remains within safe levels. Here are some of the commonly used annual dose limits for different types of radiation:
- Occupational Radiation Exposure:
- For radiation workers (those exposed to radiation as part of their job), the recommended annual dose limit is typically set at 20 millisieverts (mSv) per year averaged over five years. However, in a single year, the limit is often lower, such as 50 mSv per year, without exceeding 100 mSv in any single year.
- Public Radiation Exposure:
- For members of the public who are not occupationally exposed, the recommended annual dose limit is much lower, usually 1 mSv per year. This limit is set to ensure that the general population is protected from unnecessary radiation exposure.
It’s important to note that these dose limits are not fixed and can vary depending on the country and specific regulations. Also, certain individuals, such as pregnant women and children, may have lower dose limits to further minimize potential risks.
Radiation exposure is measured in units called sieverts (Sv) or millisieverts (mSv). The millisievert (mSv) is commonly used for measuring low levels of radiation exposure.
It’s crucial for healthcare professionals, workers in radiation-related fields, and regulatory authorities to monitor and control radiation exposure to ensure that it remains well below the recommended dose limits. This helps minimize the risk of potential health effects associated with excessive radiation exposure.
Sources
- Akram S, Chowdhury YS. Radiation Exposure Of Medical Imaging. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK565909/https://www.ncbi.nlm.nih.gov/books/NBK565909/
