[ RadSafe ] Study Estimates Radiation Dose, Cancer Risk From Coronary Artery Calcium Screening

[Cary Renquist]

Speculation upon speculation of an estimation...
These studies have the appearance of being significant (especially as
presented by the general media), but in reality they are just estimating
noise.  
I would be more interested in seeing the risk of acquiring an
antibiotic-resistant bacteria infection from repeated visits to an
imaging clinic -- I would guess that it is quite low, but probably much
higher than 0.05%.

My own speculation upon speculation of an estimation:  Implementing the
miles exposure theory of automobile liability, if an average round trip
to the imaging clinic is 20 miles, then one could expect an excess
accident incidence of 72.8 per 100,000 males for the given visit
schedule of every 5 years from the age of 45 to 75 (using the average
incident rate for males of 5.2 per million car miles, i.e. not
accounting for the increase of the rate with age).

FYI:
Using their median numbers for males, I get 65 per 100,000 using 
www.xrayrisk.com : <http://www.xrayrisk.com/calculator/calculator.php>

I also notice that the article doesn't compare the estimated additional
risk to the overall lifetime risk estimates... i.e. ~45,000 cases of
invasive cancer out of 100,000 for men.

Cary

Study Estimates Radiation Dose, Cancer Risk From Coronary Artery Calcium
Screening
http://www.medicalnewstoday.com/articles/157426.php


A study based on computer modeling of radiation risk suggests that
widespread screening for the buildup of calcium in the arteries using
computed tomography scans would lead to an estimated 42 additional
radiation-induced cancer cases per 100,000 men and 62 cases per 100,000
women, according to a report in the July 13 issue of Archives of
Internal Medicine, one of the JAMA/Archives journals.
....
"Assuming screening every five years from the age of 45 to 75 years for
men and 55 to 75 years for women, the estimated excess lifetime cancer
risk using the median dose of 2.3 millisieverts was 42 cases per 100,000
men (range, 14 to 200 cases) and 62 cases per 100,000 women (range, 21
to 300 cases)."
....
There are currently no estimates of the benefits of CT screening for
coronary artery calcification, but when they become available, they
could be compared with these estimates of radiation-induced cancer risk
to design appropriate detection and prevention strategies.