[ RadSafe ] Biological dose measures promise new view of cardiac imaging risk

Clayton J Bradt cjb01 at health.state.ny.us
Thu Apr 30 09:55:50 CDT 2009

Below is the url for a fascinating article on AuntMinnie:


It references presentations at the 2009 European Congress of Radiology, by
investigators from the Institute of Radiology, University of
Erlangen-Nürnberg, in Erlangen, Germany, and Saarland University in
Saarbrücken, Germany, who measured the direct in vivo effects of ionizing
radiation on  blood DNA in cardiac CT and angiography exams. They compare
the measurements to traditional dose-length-product and dose-area-product
measurements of radiation dose. Their technique involves counting double
strand breaks in lymphocytes before and after irradiation.

Is anyone familiar with the original studies upon which this article is

Some excerpts from the article and some questions/comments from me:

1) "Among all the biological effects of ionizing radiation in the body,
DSBs are among the most significant effects."

>>>>>What is the basis for this statement? Are we assuming DSBs cause
cancer? If so, how do asbestos fibers, benzene and human papilloma virus
cause DSBs?

2)"The exposure of mammalian cells to ionizing radiation causes DSBs within

>>>>>Why does it take so long, I would think the breaks would be
instantaneous once the secondary electron breaks chemical bonds on both
rails of the helix?

3)  "...during a normal working day, we could not find signs of biological
effects in cardiologists."

>>>>>This suggests a low dose/low dose-rate threshold for biological
damage.  Is LNT now defunct, or can someone save it?

Clayton Bradt
dutchbradt at hughes.net

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