Re: Tl-201 contaminated by Tl-202

[Elizabeth Brackett <brackett@bright.net>]

Well, I'm not a nuclear med type, but I used to do body counting and
encountered this same problem.  It was about 6 weeks after the person had
had the procedure so there was some initial panic at the plant before any
connection with it was made.  We obtained a copy of the information that
came with the Tl-201 and it listed Tl-202 as contaminant.  I believe it was
about 1% of the Tl-201 content, but because of the much longer half life it
was detectable for quite awhile.

Liz Brackett

At 10:46 AM 5/22/98 -0500, you wrote:
>
>     Question for you nuclear med HP types out there:
>     
>     An employee here received Tl-201 for some diagnostic procedure.  
>     After a considerable delay before attempted entry into the plant, 
>     he still set off alarms and was whole body counted.  Results 
>     showed plenty of Tl-202 remaining.  Two questions:  
>     Is contamination by Tl-202 relatively common for Tl-201 scans?  
>     Should we expect that contamination by Tl-202 is significant 
>     enough that it remains easily detectable for some period 
>     afterward?
>     
>     I believe this is the first time we've seen this.  Also keep in 
>     mind that our personnel detection equipment is pretty sensitive 
>     and the whole body counter has HpGe detectors so it can identify 
>     the specific isotopes at low levels.
>     
>     Thanks,  Eric Goldin
>     Southern California Edison
>     <goldinem@songs.sce.com>
>
>
>
>
******************************
  Elizabeth M. Brackett, CHP 
     Sr. Health Physicist     
     MJW Corporation, Inc.       
       (330) 644-3757        
  mailto:brackett@bright.net 
******************************