Re: Embryo/fetal doses

["A. Hancock" <a.hancock@s1.cxwms.ac.uk>]

RAY FONG wrote:
> 
> Radsafers,
> I am looking for actual (hi-profile) cases where developing
> embryo/fetus
> inadvertently received a relatively significant dose from radiographic
> imaging sources (e.g., CT, Fluoro, Abd exams, even radiopharmaceutical
> administration). Any current references/sources?
> Ray

-------------------------------------------------------------

Ray - don't send your digest next time, please. Anyway on to the
story...

I'm sorry this wasn't high profile but it was an interesting case I
worked on in 1985. On 1/8/85 a patient was given a hysterosalpingogram
(x-ray exam of uterus & etc. other bits) to diagnose possible causes of
infertility) at the West London Hospital. Subsequent to the
investigation it was discovered that at the time she had been nine weeks
pregnant. 

Our original fetal dose estimate using TLDs and a pelvic phantom was
based on 5 mins flouro screening and 5 spot films and worked out to be
in the region 4 - 15 cGys (I think these are still rads in the US).
Later it was discovered from the radiologist that the screening time was
probably only about 1 min (records of routine screening times were not
kept at this hospital). Our revised dose estimate was thus reduced to 1
- 3 cGy.

Based on the original estimate we did not advise any intervention in the
course of the pregnancy. The patient was counselled and went on, I
believe, to give birth to a healthy child, or though no follow up was
carried out. 

I've got a feeling that at the time there was something called the
"Danish Rule" which I think quoted a therapeutic termination dose of 10
rads, but I could be well wide of the mark here - anybody heard of this?

Cheers

Andy Hancock
Charing Cross Hospital
London, UK
a.hancock@cxwms.ac.uk