Low-Dose Radiation of Infants May Affect Later Intellect

A study by Swedish researchers has found that low doses of ionizing radiation in infancy can affect intellectual capacity in later life. Their findings were reported in the January 3, 2004, issue of the British Medical Journal.

The study involved 3,094 men who had received radiation therapy before the age of 18 months during 1930-1959. At age 18 or 19, their intellectual capacity was tested and high school attendance was recorded. The proportion of boys who attended high school decreased with increasing doses of ionizing radiation to both the front and back parts of the brain. A significant dose-related response was also found for learning ability and logical reasoning but not for spatial recognition.

Computed tomography (CT) scanning, which delivers high doses of ionizing radiation, is increasingly being used in young children after minor head trauma. Intellectual development could be adversely affected when the infant brain is exposed to ionizing radiation at doses equivalent to CT scans of the skull, say the authors. The risks and benefits of CT scans in minor head trauma need to be re-evaluated, they conclude. The study was conducted by Per Hall, associate professor, Karolinska Institute (Stockholm, Sweden) and colleagues.




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