Re: MDL and Dose Effects - opinionated response -Reply

[David Scherer <scherer@uiuc.edu>]

>Dave:
>You're citing the exception that proves the rule.
>Not one dentist or internist in a 1000 with an xray machine knows what
>ALARA means, let alone keeping ALARA records, setting ALARA goals etc,
>ad nauseum. Sure dentists often use a Pb impregnated rubber blanket, but
>they have no idea what the dose saving is, or for that matter what the
>dose to the skin is from a full mouth xray. Sure, some few steps have
>been taken to reduce dose from routine dental and medical xrays, but
>where is the ALARA justification for those xrays in the first place.
>Perhaps an ALARA discussion and justification takes place on a
>case-by-case basis somewhere, sometimes, but surely not in 90%+ of all
>the medical/dental xray scenarios.
>
Wade and group:

I do not mean to imply that everything in health care is perfect.  Of course
there is a wide variety in quality, just as there is a wide variety in
radiation safety programs among the many licensees in this country.  What I
challenge is the statement that, "We spend ... nothing at all on ALARA where
the dose are the greatest, the medical field."

A lot of money is spent on safety features, even in a conventional x-ray
machine.  Money has gone into developing (and buying) faster film-speed
combinations, image intensifiers, pulsed fluoroscopy, digital radiography,
FS mammography, etc.  In therapy, a lot has been spent on linear
accelerators, treatment planning, and conformal radiation therapy, all in
order to deliver less dose to healthy tissues.  There are costs for on-going
QA procedures (e.g. daily film processor testing, regular testing and
maintenance on x-ray machines, daily dose calibrator and gamma cameras
tests, etc.)  All of these result in reduced patient doses.

Agreed, many doctors do not know as much about radiation science as we do.
(Neither do all rad workers in academia or industry).  But many of the
safety features have been engineered into the system and the procedures.
Once the lead apron has been designed, does the dentist need to know what
its attenuation factor is?  Once a cabinet x-ray enclosure is built, does
the user need to know the attenuation factor?  Would I like for all health
care workers to know more about radiation hazards?  Of course.  And many
people are working hard to provide that expertise.  But imperfection is a
far cry from saying nothing is done to reduce patient doses.

I don't feel I can answer the question of whether all exams are needed.  I
worked for a little while with a dental radiologist.  (Yes, there is such a
thing.)  He tells me that so much of the tooth and alveolar bone that holds
it in place is below the gum that an exam without an x-ray is almost
useless.  Who am I to argue?  On the other hand, I have no idea how much of
the radiation use on this campus will ultimately produce important results.
I don't prejudge the results of the research or of the x-ray study.

Regards,
Dave Scherer
scherer@uiuc.edu