Re: Sm-153

[carol marcus <csmarcus@ucla.edu>]

At 06:14 PM 1/28/00 -0600, you wrote:
>Louis,
>
>How much is "usually" left after a "typical" administration?
>As you know, that 10 CFR part 20 has an exempt quantity for Eu-154.
>Is amount of "left over" Eu-154 above that value? I do not have any Regs with 
>me.
>(May be I should?)
>Or the regulators do not want to see ANY delectable activity of Eu-154 to be 
>disposed.
>
> >> 
>In fact, the actual
>measured values range from 0.06 to 0.08 microcuries of Eu-154 per
>millicurie of Sm-153.
>>>
>
>Emil.
>
>In a message dated 1/28/00 3:24:08 Pacific Standard Time, 
>Louis_Hagler@BERLEX.COM writes:
>
><< appropriate for Sm-153, with a half-life of nearly 2 days.  However,
> because of its long half-life, it will be possible to detect, well beyond
> 20 days, the microcurie amounts of Eu-154 that remain in the vial after
> administration of Quadramet.
>  >>
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Dear Emil:

You raise interesting questions.  I always flush the syringe ten times with
physiologic saline from the running IV after administering Quadramet.  My
RSO has measured the quantity of Sm-153 remaining in the syringe and needle
after this procedure in 3 cases after flushing.  Figure 1E-6 to 1E-5 as the
factor for remaining activity, and virtually all of it is in the needle and
needle cap (which does not get flushed), not the syringe. The activity of
Eu-154 that remains is assumed to be proportional to the activity of Sm-153
that remains (a valid assumption), and is below the level in 10CFR Part 20
that requires being labeled "radioactive".  It is also within the IAEA
standards for disposal as non-radioactive waste, if you are in a country
that uses the IAEA standards.  If you are in the USA, and are concerned
about waste disposal, I will tell you that California Rad Health has
recommended putting in a 10 CFR Part 20.2002 amendment to your license to
dispose of it as non-radioactive trash; presumably this would hold in other
States, although I don't know that anyone is bothering to do so.  As it does
not have to be labeled "radioactive" after 3 weeks of storage, it is
reasonable to not treat it as being radioactive, and disposing of it as
non-radioactive waste.

Ciao, Carol

Carol S. Marcus, Ph.D., M.D.
<csmarcus@ucla.edu>

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