From the Guidelines
The maximum acceptable radiation exposure per year is 1 millisievert (mSv) for the general public, while occupational workers can receive up to 20 mSv annually averaged over five years, with no more than 50 mSv in any single year, as established by regulatory guidelines to minimize health risks. When considering radiation exposure, it's crucial to understand the context and the source of the exposure. The study by Boone et al 1 discusses the concerns about increasing exposure to ionizing radiation from computed tomographic (CT) scanners and the need to pool scientific and technical knowledge about the potentially adverse effects of low levels of ionizing radiation. Key points to consider include:
- The effective dose of ionizing radiation from medical imaging is measured in units called millisieverts (mSv) [ 1 ].
- There is evidence of adverse effects at higher doses, with an incremental increase in the incidence of various types of cancer compared with incidence of such cancers in the unexposed population at doses greater than 100 mSv [ 1 ].
- Regulatory bodies have established safety thresholds based on the linear no-threshold model, which assumes even small radiation doses carry some risk [ 1 ].
- For occupational exposure, additional limits are set for specific body parts, such as 150 mSv for the lens of the eye, and 500 mSv for the skin and extremities [ 1 ].
- Pregnant radiation workers have a lower limit of 1 mSv for the developing fetus during pregnancy to ensure minimal risk [ 1 ]. These guidelines and limits are designed to balance the need for radiation use in medicine, industry, and research while protecting public health and safety.
From the Research
Maximum Acceptable Radiation Exposure
The maximum acceptable radiation exposure per year is not explicitly stated in the provided studies. However, some studies provide information on the average radiation exposure from natural sources and the effective dose equivalent of various radiologic examinations.
- Average radiation exposure from natural sources: 2.4 mSv per year in Germany 2
- Effective dose equivalent of chest radiography: 0.06 to 0.25 mSv 2
- Effective dose equivalent of computed tomography (CT) scans: 3-27 mSv using conventional examination parameters, and 0.3-0.55 mSv using low dose CT settings 2
Radiation Exposure Limits
While the studies do not provide a clear maximum acceptable radiation exposure limit, they do discuss the risks associated with radiation exposure and the need to balance these risks with the benefits of radiologic examinations.
- The International Commission on Radiological Protection suggests that an effective dose equivalent of 1 mSv would lead to 5 additional malignancies in 100,000 individuals exposed 2
- The studies highlight the importance of minimizing radiation exposure, particularly in children, and the need for further research to understand the risks associated with CT-induced radiation exposure 3, 4, 5
Comparison of Radiation Exposure Levels
The studies provide information on the radiation exposure levels associated with different radiologic examinations, including chest radiography and CT scans.