Post by beebs on Jun 13, 2012 16:39:04 GMT -5
This article is article concerns children and risk of cancer
from RFs emitted by CT scans. I found similar articles
concerning cancer risks in adults.
Childhood CT Scans Linked to Later Leukemia, Brain Cancer
Laurie Barclay, MD
Authors and Disclosures
June 7, 2012 — Children undergoing computed tomography (CT) scans with cumulative radiation doses of about 50 mGy had about triple the risk for leukemia, and those who received doses of about 60 mGy had nearly triple the risk for brain cancer, according to the results of a retrospective cohort study published online June 7 in the Lancet.
"We've been doing this particular study for about 8 years, and it's been about 20 years of research at Newcastle on radiation effects," lead author Mark Pearce, PhD, from Newcastle University and Royal Victoria Infirmary, United Kingdom, said in a news conference. "We found that radiation exposure from CT scans in childhood could triple the risk of leukemia and brain cancer."
The study authors note that CT scans are very useful diagnostically, but that children are more radiosensitive than adults and may therefore have additional potential risks for cancer from ionizing radiation. The study goal was to determine the excess risk for leukemia and brain tumors after CT scanning in a cohort of children and young adults.
Youth younger than 22 years and without previous diagnoses of cancer who first underwent CT scanning in National Health Service (NHS) centers in England, Wales, or Scotland between 1985 and 2002 were included in the analysis. The investigators estimated absorbed brain and red bone marrow radiation doses per CT scan in megagrays.
The NHS Central Registry provided data for cancer incidence, mortality, and loss to follow-up from January 1, 1985, to December 31, 2008. Use of Poisson relative risk models allowed assessment of excess incidence of leukemia and brain cancer. To exclude CT scans associated with cancer diagnosis, follow-up for leukemia started 2 years after the first CT, and for brain cancer 5 years after the first CT.
Diagnosis of leukemia during follow-up occurred in 74 of 178,604 patients, and diagnosis of brain tumor in 135 of 176,587 patients. There was a positive association between radiation dose from CT scans and leukemia (excess relative risk [ERR] per mGy, 0.036; 95% confidence interval [CI], 0.005 - 0.120; P = .0097) and brain tumors (ERR, 0.023; 95% CI, 0.010 - 0.049; P < .0001).
Compared with patients who received a radiation dose of less than 5 mGy, those who received a cumulative dose of at least 30 mGy (mean dose, 51.13 mGy) had a relative risk of leukemia of 3.18 (95% CI 1.46 - 6.94). For patients who received a cumulative dose of 50 to 74 mGy (mean dose, 60.42 mGy), the relative risk of brain cancer was 2.82 (95% CI, 1.33 - 6.03).
"Our main findings were confined to children under the age of 15 years, and showed that the risk of brain cancer is tripled with 2 or 3 CT scans, and the risk of leukemia is tripled with 5 to 10 CTs," Dr. Pearce said. He added that the risks vary with age and with radiation exposure of a particular type of CT scan to a given target organ.
Cont/...www.medscape.com/viewarticle/765223?sssdmh=dm1.791635&src=nldne