[ RadSafe ] In utero dose

[John Jacobus]

Keith,
The first consideration in an emergency is to the
patient who is the woman.  The assessment of critical,
life-threatening injuries are paramount.  If the
patient dies, so will the fetus.  

Generally, efforts will be made to protect the fetus
will be made.  This includes efforts during surgery
and any other medical treatment.

Generally, a medical or health physicist SHOULD be
contacted to determine the dose to the exposed or
potentially exposed fetus.  NCRP Report 54, "Medical
Radiation Exposure of Pregnant and Potentall Pregnant
Women" is a good source for determining dosage and for
information on risks.  The risks should then presented
to the woman by her physician.  It is important to
remember that it is THE WOMAN'S DECISION on
termination of HER pregnancy.  From the best knowledge
available, there is a very small increase of risk
below 10 rads of exposure beyond the normal incidence
rates.  For example, the estimate increase in leukemia
for a fetus receiving 2 rads is 1 in 2,000, which is
lower than the normal leukemia incidence rate in
siblings is 1 in 720.

In a typical pregnancy, the normal incidences of a
malformation are 5% and for a spontaneous abortion, it
is 15%.  

--- Keith Welch <welch at jlab.org> wrote:

> I have some questions for you medical experts.  I'm
> curious what 
> guidelines are used when there is a case requiring
> x-rays of a pregnant 
> female.  Let me give you a hypothetical case.  Let's
> say a woman is 
> injured in an auto accidedent, has some internal
> injuries and broken 
> bones.  She's 12 weeks pregnant.  To treat her
> injuries, she needs 
> surgery and a series of radiographs.  Are there
> generally accepted and 
> well known standards that physicians refer to in
> order to advise 
> patients and determine a course of treatment?  ARe
> there risk-based 
> guidelines in place and widely known to general
> surgeons and 
> practicioners?  How common is it for a surgeon to
> seek the advice of an 
> HP or MP to assess the risks of such procedures?  
> My impression of the 
> handling of "routine" x-rays is that if a woman is
> pregnant, x-rays are 
> always postponed, just to be conservative.  But in a
> case where there is 
> a pressing need to preserve health, how is the
> decision to conduct the 
> x-rays arrived at?  How are these risks weighed? 
> What is the typical 
> "standard of care"?  Is there an agreed dose at
> which the patient is 
> advised to terminate the pregnancy?
> 
> Thanks.
> Keith Welch
> 

+++++++++++++++++++
"A scientist's aim in a discussion with his colleagues is not to persuade, but to clarify." 
Leo Szilard
-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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