Re: Mammography Doses

[Alan Aqualino <aa2h@holmes.acc.virginia.edu>]

        A large number of health physicists appear dumbfounded
that an xray tech has trouble answering "What dose am I getting
from this xray study?".  In the case of a mammogram, I DO think
an approximate (with qualifications) can be given immediately -
if not by the tech, then by a medical physicist or radiologist
who can explain what is meant by mean glandular dose.
(Although assigning a risk factor to that dose is what the
patient probably really wants, and that would be more difficult.)
	But if a patient getting a chest xray or a CT asks what
dose they're getting, the tech first has to guess at what the
patient is really asking.  What does this patient mean by
"*THE* dose"?  (There are lots of doses - do they mean at the
surface, at 2 millimeter depth, at 10 centimeter depth, or
what?  Is there a specific organ the patient is worried
about?)  Do they understand how field size figures in when
analyzing biological risk?  Will a quick answer cause them to
worry unnecessarily?  (Suppose a woman having a head CT is told
her "dose" is roughly 2 rads - if she turns out to be pregnant,
is she going to worry for 9 months that the *fetus* got 2
rads?)  And remember, the tech xrays a new patient every
10 minutes or so - even a 60 second explanation per patient can
cause the schedule to back up for the rest of the day, leading
to an unhappy waiting room.
	Before we health physicists criticize the radiologic
technologists, perhaps we should be a little more judicious in
the way we ask our questions.  Rather than berating the tech,
ask them to write down the technique (equipment) factors they
used for your xray, get the name of the physicist who surveyed
the xray equipment, and ask said physicist the questions.  The
tech's expertise is in other areas.