Re: radiopharmaceutical patient release

[Kent Lambert <lambert@allegheny.edu>]

JMUCKERHEIDE@delphi.com wrote:

> If the patient is at essentially no risk with the material in them, why would
> a rational person consider that the much lower dose to others is significant?
> (excusing the practioner or another party who is continuously exposed to many
> patients and procedures).

There are clearly non-stochastic effects from the administration of
20-30 mCi of I-131 to patients (doses for treating hyperthyroidism). 
There are clearly non-stochastic effects from the administration 4 mCi
of Sr-89 for bone pain.  There are clearly non-stochastic effects from
the administration of I-125 as a permanent implant to treat interstitial
cancer.  Therefore, the "if" of your 'If/then" argument is not valid for
therapeutic administrations.  

If a patient is treated as a outpatient for Graves disease, gets on an
airplane, and gets airsick, then a significant amount of I-131 can be in
the vomitus.  I have measured 1 mCi out (of a 150 mCi administration) in
the vomitus from a patient that got sick 8 hours post administration. 
What's the dose rate to the skin from this?  Assuming 1 mCi on 100 cm^2
it's 63 rad/h of contact time.  That results in erythema in 5 hours of
contact time.  Without instructions, how is someone to know that careful
and prompt washing (or removal of contaminated cloting) is important?

 
--
Kent N. Lambert, CHP
lambert@allegheny.edu

My employer takes no credit for opinions
expressed by this writer.