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Medical radiation

Recent evidence on the risks of very low-level radiation, Dr Ian Fairlie, January 17, 2013 “…...2. Medical Exposures

Most exposures from medical diagnostic procedures are relatively low, and although their collective doses are increasing in most developed countries, in almost all cases they are justified by their clinical benefits. Nevertheless there have been a score or so of articles in scientific journals in recent years expressing concern about the risks of increased doses from CT scans, especially to children. Even the WHO has issued a draft report expressing the need for more vigilance.

In order to investigate these concerns, Pearce et al (2012) conducted a massive UK retrospective cohort study of computed tomography (CT) scans among 178,000 patients. The team estimated absorbed brain and red bone marrow doses per CT scan and assessed the excess incidence of leukaemia and brain tumours cancer with Poisson relative risk models. They observed a positive association between radiation dose from CT scans and leukaemia (excess relative risk [ERR] per mGy = 0·036, 95% CI 0·005–0·120; p=0·0097); and a positive association with brain tumours (0·023, 0·010–0·049; p<0·0001). They found CT scans caused statistically significant increases in cancer risks in under three-year olds: three head scans tripled their risk of brain cancer and five to ten scans tripled their risk of leukemia. Although the authors did not comment on these risks, there is no doubt that these are large risk increases from relatively small doses.

I shall be writing more on this matter in due course.

In Canada, similar risk increases were observed by Eisenberg et al (2011) after low-dose exposures from cardiac imaging in adult patients with acute myocardial infarction. For every 10 mSv from cardiac imaging, a 3% increase in cancer risk (RR= 1.03 per 10 mSv, 95% CI = 1.02–1.04) was observed. The authors stated “These results call into question whether our current enthusiasm for imaging and therapeutic procedures after acute myocardial infarction should be tempered.”…….http://www.ianfairlie.org/news/recent-evidence-on-the-risks-of-very-low-level-radiation/

January 18, 2013 - Posted by Christina Macpherson | 2 WORLD, health