Diagnostic pediatric computed tomographic scans of the head: actual dosage versus estimated risk

Recent publications have implicated computed tomographic scans in the genesis of cancer and developmental delay. To determine whether the imaging protocols used in the authors' craniofacial practice could be harmful, they reviewed patient radiation exposure data for 77 patients. They then reviewed the literature concerning the documented effects of low linear energy transfer received during radiation and the application of the linear no-threshold hypothesis.

This is a retrospective single-institution analysis of the senior surgeon's (A.D.) patients who underwent computed tomographic scanning of the head and face. Patient data from the years 2001 through the first half of 2008 were reviewed and the authors evaluated those who had radiation dose reports for each computed tomographic examination.

Newly diagnosed craniosynostosis patients underwent an average of 1.74 computed tomographic scans per year at an average dose of approximately 1.39 mSv. Syndromic patients had a higher total number of studies when compared with nonsyndromic patients (9.73 versus 4.11). In comparison with published data, the level of radiation received by the authors' patients for computed tomographic scans of the head was 100 to 1000 times less than those levels shown to increase carcinogenesis, and nearly 40 times less than that shown to purportedly affect development and cognition.

The authors suggest that published experimental evidence does not support the linear no-threshold model at low linear energy transfer levels similar to the exposure of their patients undergoing computed tomographic scans of the head. In addition, no convincing epidemiologic data exist demonstrating an increase in cancer incidence for doses below 100 mSv.