Re: Internal v. skin

[eport@nwu.edu (Eli A. Port)]

Consider physics.  The energy from a quantity of beta emitter on a 
small area of skin is deposited in a relatively small mass.  The energy 
from the same quantity of an internal emitter is usually deposited in 
a much larger mass.  

Dose = energy/mass.

At 11:16 AM 2/21/96 -0600, radsafe@romulus.ehs.uiuc.edu wrote:
>
>Regarding Kent Lambert's original post (16 Feb 1996 (Digest 826)), "One 
>should keep in mind that a microcurie of an electron emitter delivers a much 
>smaller dose when it is in the body that it does when it is on the the skin. 
> And skin contamination is much more likely than an uptake.  Therefore, the 
>most critical concern has to be skin contamination."
>
>And js_dukelow's 2/16/96 query, "Am I missing something here?"
>
>If you read this with your RSO hat on,  it does make sense!  Let's take a 
>look at P-32:  The dose conversion for 1 microcurie/cm2 on the skin is 8 
>rem/h.  The dose conversion for 1 microcurie ingested is about 10 mrem CEDE. 
> Therefore, in just over six hours of a 1 microcurie/cm2 skin contamination 
>event (assuming no removal) you have an overexposure!  On the other hand, 
>(no pun intended) the ingestion event only delivers 1/600 of the ALI.  Of 
>course we could get out our pencils and sharpen up the analysis, but it 
>won't have much effect on the bottom line -- the skin contamination event is 
>typically much more likely to cause a regulatory overexposure than an 
>ingestion or inhalation event at a biomedical R&D lab.
>
>This is my opinion and not necessarily the opinion of my employer.
>
>glenn_sturchio@merck.com
>
>
>
ELI A.PORT, CHP, CIH, P.E.
RSSI
eport@nwu.edu
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