Evidence for Carcinogenesis
There are two large studies that suggest an association between irradiation in utero and childhood malignancy (usually leukaemia)
- The Oxford Survey was a retrospective case-controlled study, and demonstrated that a higher proportion of children who died from leukaemia had been irradiated in utero (relative risk 1.52)
- A follow up study in New England also showed a link between radiation in utero and leukaemia before the age of 15.
A review of all the available data by Doll and Wakeford in 1997 suggested that there was a causal relationship, the magnitude of which was hard to estimate.
Risk of Prenatal Radiation Exposure
The important numbers are:
- Obstetric x-ray examination increases the risk of childhood cancer by 40%, with doses over 10 mGy
- There is an absolute increase in risk of 6% per Gy.
These numbers are uncertain due to difficulties in acquiring sufficient numbers of patients to study.
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