[ RadSafe ] CT scans dangerous?
crispy_bird at yahoo.com
Thu Nov 8 07:40:09 CST 2007
You are comparing individual to populaton doses. And,
as you noted, the risk is a calculated one for the
population of children. How does one compare the use
of a CT scan to child who was in a car accident to not
doing the CT scan? You are optimizing the use of the
technology to help the patient. Obviously, you cannot
say which of the 18 000 children receiving a CT scan
will develop cancer FROM the radiation. But if the
child dies because you do not perform the CT scan,
that is a non-statistical result.
Nevertheless, it is also possible to overprescibe CT
scanning. I doubt that every child who falls and hits
their head should get a CT scan. (Beyond the
radiation dose, there is the cost of such procedures.)
There are guidelines for medical intervention in many
branches of medicine. I believe that guidelines have
been been developed for emergency rooms on the usage
of CT scans.
Apart from the use of radiation in medicine, there are
cases where CT scanning has been sold to asymptomatic
"customers" http://www.fda.gov/cdrh/ct/ Unless a
patient derives a medical benefit, I would think we
should oppose this waste of resources.
One question: is the increased risk of 0.29% for the
population who are receive a CT scan? [9.5 additonal
deaths] / [18 000 population] is an increase of 0.05%.
In the population receiving CT scans.
--- ××¨××§× ×¨ ×× <brickner at smile.net.il> wrote:
> The message of the paper is not "Stop the cameras".
> It means to provide the pediatritions a tool to
> assess the risk against the benefit at time of
> decision. They calaulated the lifetime excess risk
> to die (from cancer)from about 18000 CT examinations
> performed on children each year in Israel. The
> calculation were done with existing models (I think
> they used BEIR V coefficients, standartised to the
> children population). They estimated the risk of
> 0.29% corresponding to 9.5 excess mortality cases.
> Personally I think that I, and every other
> physician, can live with this estimation.
> Dov Brickner MD
> Beer Sheva ISRAEL
> -----Original Message-----
> From: John Jacobus [mailto:crispy_bird at yahoo.com]
> Sent: Saturday, November 03, 2007 4:59 AM
> To: ???÷?? ??; radsafe at radlab.nl
> Subject: RE: [ RadSafe ] CT scans dangerous?
> Dr. Brickner,
> Does that cited paper have any evidence of mortality
> due to CT scans? How do the projected risks compare
> to the immediate benefits derived from the CT scans?
> --- áøé÷ðø ãá <brickner at smile.net.il> wrote:
> > I am not sure that ALARA does not apply to medical
> > exposures. It is true
> > that justification considerations are limited (and
> > the decision to perform a
> > CT exam is made on medical basis), but
> > should be applied in
> > certain situations like a pregnant woman or
> > exams in children
> > ("complex situations" as they are called in ICRP
> > 60). Optimiztion should be
> > applied at the level of the imaging department or
> > institution (see ICRP 60
> > 179-184).
> > The subject was discussed in Israel lately :
> > G et al. Excess
> > lifetime cancer mortality risk attributable to
> > radiation exposure from
> > pediatric computed tomography examinations .
> > Med Assn J 2007 ;
> > 9:579-82 (paper written in English if anybody is
> > interested I can try to get
> > a pdf copy) .
> > Dov Brickner MD
> > Beer Sheva ISRAEL
"If you guard your toothbrushes and diamonds with equal zeal, you'll probably lose fewer toothbrushes and more diamonds."
- Former national security advised McGeorge Bundy
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird at yahoo.com
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