Study reviews the risk of cancer following low and moderate estimated doses of ionising radiation in early life

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This paper reviewed studies on the risk of cancer or benign neoplasms following low or moderate doses of ionising radiation in utero or in childhood from medical and environmental sources. The literature search identified 60 studies that were included in this review and meta-analyses were conducted. The review found excess cancer risks associated with both in utero and childhood exposures. For childhood exposures this occurred at low radiation dose levels of less than 0.1 Gy, and for in utero exposures this occurred at levels around 0.02 Gy. This review was mainly focused on leukaemia but also found evidence of an increased risk in brain/central nervous system cancers, as well as thyroid cancer. The authors conclude that childhood cancer risk is increased in the low radiation dose range of less than 0.1 Gy. These findings are further supported by a separate review conducted by Little et al. on medical diagnostic radiation exposure in early life without quantitative estimates of dose which reached a similar conclusion (a review of this study by ARPANSA can be accessed here).

Review of the risk of cancer following low and moderate doses of sparsely ionising radiation received in early life in groups with individually estimated doses

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Moderate and high doses of ionising radiation at high dose rates are known to be associated with an increased risk of cancer. However, this review presents evidence of an increased risk of cancer at low radiation doses (less than 0.1 Gy). Special concern in relation to radiation protection is afforded to children, and women of child-bearing age with most diagnostic radiology procedures posing little risk to the mother or foetus. The Code for Radiation Protection in Medical Exposure (2019) (RPS C-5) sets out the Australian requirements for the protection of patients, including pregnant women and children, relating to their exposure to ionising radiation. While the (Little et al) study’s meta-analysis supports a statistically significant increase in cancer risk for low radiation exposure, the increase is very small, and the risks should be assessed against the benefits of having the procedure. ARPANSA advises parents concerned about their children’s exposure from radiological procedures to talk to the doctor requesting the radiological procedure. The child’s doctor and the staff at the radiology facility should work together on which tests are required and evaluate the risks and benefits in each child’s individual circumstances. If there are still questions at the radiology facility, these can be raised with the radiology team during the consent process before the imaging proceeds.