Re: Extremity Doses and Iodine

["Sandy Perle" <sandyfl@ix.netcom.com>]

Depending on the isotope worked with, and how a contamination check 
is performed, and with what type of instrumentation, it is plausible 
that there could be contamination and not be detected by a 
contamination frisk. In my "lifetime" I have assessed dosimeters that 
have been contaminated, a high dose response was observed, and the 
contamination check didn't display any unusual reading. Other
points that needs to be made are:

1. When the badge was worn (time frame). Time from "potential" 
    contamination until it is received by your processor can be two 
    months for a montly ring, and 4 months for a quarterly ring.

2. Energy spectra ...  daughter product is Xe-125.

3. Half-life of the material that "potentially" contaminated the 
    dosimeter. It could be that the dosimeter was receiving an 
    exposure from the contamination for a considerable time, and when 
    the dosimeter was received for processing, the levels could be 
    significantly reduced. An analogy, internal deposition, body 
    burden performed later (if not known that there was an upatke) .. 
    what is the true dose to be assigned, and is it valid. I-125 has 
    a ~ 60 day t 1/2. 

Bottom Line: Regulatory Agency is misinformed if they are relying on 
a processor to "validate" ALL contamination issues.



------------------
Sandy Perle
Technical Director
ICN Dosimetry Division
Costa Mesa, CA 92626
Office: (800) 548-5100 x2306 
Fax:    (714) 668-3149
  
mailto:sandyfl@ix.netcom.com
mailto:sperle@icnpharm.com

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