¦^ÂÐ¡G Re: [ RadSafe ] Disposal via Decay in Storage

Fri Nov 18 12:02:18 CST 2005

Khalid,
While your generally comment about initial activity
and time held until release is true, the use of Tc-99m
is a bad example.  If you wait 7 days, the reduction
in activity is 3.7 X 10^-7 per cent.  If the monthly
release limit for Tc-99m is 0.01 microcurie/ml from
Appendix B to Part 20--"Annual Limits on Intake (ALIs)
and Derived Air Concentrations (DACs) of Radionuclides
for Occupational Exposure; Effluent Concentrations;
Concentrations for Release to Sewerage"
http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/appb/Technetium-99m.html
you would have to have start with about 267 curies of
Tc-99m.

--- Khalid Aleissa <kaleissa at kacst.edu.sa> wrote:

> Exactly .... this is my point too ... Waiting more
> than 7 half-lives will 
> reduce the activity to less than 1% but what would
> be the exempted level for 
> example for Tc99m to discard.
> 
> Khalid
> 
> ----- Original Message ----- 
> From: "Leung Kim Cheung" <lrccrm at yahoo.com.hk>
> To: "RADSAFE List" <radsafe at radlab.nl>
> Sent: Saturday, November 12, 2005 4:36 AM
> Subject: ¦^ÂÐ¡G Re: [ RadSafe ] Disposal via Decay
> in Storage
> 
> 
> > This question is always in my mind that if time is
> the only one parameter 
> > we considered, then how about a large quantitiy of
> Tc99m? 1mCi and 100mCi 
> > Tc99m decay to different activity after 1 weeks.
> >
> > Samuel Leung
> >
> > John Jacobus <crispy_bird at yahoo.com> »¡¡G
> > Khalid,
> > Just wait a week and it decays away.
> >
> > --- Khalid Aleissa wrote:
> >
> >> I believe that the question still is not answered
> >> ... how we get rid of
> >> Tc-99m ...
> >>
> >> Khalid
> >> ----- Original Message ----- 
> >> From: "Baratta, Edmond J"
> >> To: "'Cary Renquist'" ;
> >> "RADSAFE List"
> >>
> >> Sent: Thursday, November 10, 2005 6:43 PM
> >> Subject: RE: [ RadSafe ] Disposal via Decay in
> >> Storage
> >>
> >>
> >> >
> >> > Technetium-99m has a six (6) hour half-life.
> >> After sixty (60) hours it
> >> > should have decayed away. This is
> >> radiopharmaceutical that is commonly
> >> > used. That's why it is popular, otherwise we
> >> would have people walking
> >> > around who are 'hot'.
> >> >
> >> > Edmond J. Baratta
> >> > Radiation Safety Officer
> >> > Tel. No. 781-729-5700, ext 728
> >> > FAX: 781-729-3593
> >> >
> >> > This is my opinion and not those of my Agency.
> >> >
> >> >
> >> > -----Original Message-----
> >> > From: radsafe-bounces at radlab.nl
> >> [mailto:radsafe-bounces at radlab.nl] On
> >> > Behalf
> >> > Of Cary Renquist
> >> > Sent: Wednesday, November 09, 2005 6:02 PM
> >> > To: RADSAFE List
> >> > Subject: [ RadSafe ] Disposal via Decay in
> Storage
> >> >
> >> > Quick question:
> >> >
> >> > Is Tc-99m a candidate for disposal via
> >> > decay-in-storage?
> >> >
> >> > If so, what would be a acceptable method for
> >> > monitoring the decayed material prior to
> release?
> >> >
> >> > Thanks for any info.
> >> > Cary
> >> >
> >> > _______________________________________________
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> >
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> > Truman asked Americans to refrain from eating meat
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> > -- John
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> >
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+++++++++++++++++++
"Efforts and courage are not enough without purpose and direction."
"John F. Kennedy, U.S. President and former Naval Officer 

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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