Re: Beta Emitters and Dose Calibrators

["John R. Laferriere 671-8316" <John.R.Laferriere@dupontpharma.com>]

Carol- You wrote:

"Your assumption that more precision is needed for therapy than
diagnosis is dead wrong.  Many diagnostic tests require more precision
because of the technique and data processing involved.  Any old amount of
I-131 can treat hyperthyroidism, and if it isn't enough the first time, you
give a second or third dose.  The same patient can go to 2 doctors, and one
could prescribe 2 mCi and the other 30 mCi
and each doctor would manage to cure the disease.  

Ciao, Carol"


Darn!  I hate it when I'm dead wrong.  But seriously, is your hyperthyroidism
argument really representative?  There must be a fairly wide safety margin 
between a theraputic dose and a harmful dose when you're hitting the thyroid
with I-131.  I would doubt whether any other theraputic nuclear medicine has
as high a safety margin, just based on what I know about the dosimetry and
metabolism of radioiodines (correct me if I'm wrong).  And who knows what the 
future will bring in the area of B- oncology agents.  Safety margins for 
potentially life saving oncology treatment may be much slimmer.  As you know,
this is a dynamic field with lots of possiblities on the horizon.  I guess
my main point is that it does not seem prudent to so quickly and casually
dismiss the accuracy of beta emitter assays as a non-issue with no
impact on the patient.


John Laferriere, CHP
DuPont Pharmaceuticals Co.
Medical Imaging Division
john.r.laferriere@dupontpharma.com
Standard Disclaimers






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