MDs and radiological sciences

["Gibbs, S Julian" <s.julian.gibbs@vanderbilt.edu>]

Having taught medical students for more than a quarter 
century, I think I may be entitled to enter some comments.
Are HPs aware that medical education encompasses 
essentially all of modern biology, most of chemistry, a big 
chunk of physics, plus a number of lesser subjects.  It is 
simply not possible to provide expertise in depth in the 
whole gamut.  Enter specialty training, where the breadth 
is greatly diminished but depth is increased.  I teach 
radiobiology to our residents now in specialty training for 
diagnostic radiology.  Some years ago, I had the equivalent 
of a one semester hour course to cover this--modest but 
adequate.  Now, with the advent of more clinical 
procedures (magnetic resonance, computed tomography, 
ultrasound, positron emission tomography, interventional 
angiography, etc.) I have only 5 lecture hours.  I 
understand that this is probably typical of other radiology 
residency programs.
Most diagnostic imaging procedures deliver very small 
radiation doses to patients.  The upper limit is of the 
order of 10 mGy, for some CT, angiography, etc.  In my 
teaching I try to point out that there is now disagreement 
among competent scientists as to the presence and/or extent 
of risk from these procedures.  We conclude that if there 
is a risk, it must be vanishingly small, and never 
sufficient to warrant cancellation of a medically justified 
procedure.
Some interventional procedures deliver larger doses. 
Epilation, erythema, and even moist desquamation are not 
unknown.  These involve doses of the order of a few Gy, and 
harmful sequellae might be expected.  However, these 
procedures are generally livesaving and may eliminate 
extensive surgery, the risk of which may be much greater.

I think that the best we can hope for is some in-depth 
knowledge among radiologists but less in other physicians.  
I try to emphasize to my radiology students (and to other 
medical students in my infrequent contacts with them) that 
when faced with a radiation exposure problem they should 
not rely on their memory, but rather should contact their 
friendly academic medical center for current information.

Finally, I wonder why HPs do not relegate these issues to 
radiobiologists, who are really the competent ones to 
evaluate available data.  I know that when I (as a 
radiobiologist) dabble in physics I can easily 
misunderstand some of the sophisticated issues.  My 
physicist friends tell me they experience the same when 
they get into modern biology.

***********************************************************
S. Julian Gibbs, DDS, PhD               Voice: 615-322-1477
Professor, Emeritus                       FAX: 615-322-1474
Dept. of Radiology & Radiological Sciences
Vanderbilt University Medical Center
209 Oxford House
Nashville TN 37232-4245        Email:j.gibbs@vanderbilt.edu
***********************************************************
"Under democracy each party always devotes its chief energies
to trying to prove that the other party is unfit to 
rule -- and both commonly succeed, and are right." 
                -- H. L. Mencken (1880-1956)  



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