Tl-201 contaminated by Tl-202

[goldinem@songs.sce.com]

     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>