Re[2]: Electronic Dosimetry

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

The questions regarding Electronic Dosimetry are the very questions 
that should be addressed for "any" dosimeter to be used as an 
"official" dose of record.  The facility needs to be able to address 
the following:

1) Work environment, radiation mix and dose rates to be monitored.

2) Any external factors that could adversely change item 1 above, 
     i.e., radiation mix during a transient situation whereby the 
     energy spectra and radionuclides to be monitored are drastically 
     different that the normal work environment.

3) Normal Business and Standard of Care provided to the workers, 
     current and past, and, reasons used to change them.

4) Reliability and Availability of the dosimeter used.

5) Degree of testing performed by the facility, "beyond" 
    accreditation proficiency testing. It is one thing to NVLAP or 
    DOELAP accredit a dosimeter in a limited capacity and find that 
    the dosimetry needs for measurement change as the environment 
    changes.

6) NVLAP and DOELAP criteria is not very substantial as far as 
    "passing" proficiency testing. I abhor individuals telling me 
    that their dosimeter passed the accreditation testing. To remind 
    everyone, NVLAP passes a dosimeter proficiency test with a
    |P-Bar| + s < 0.5 (Categories III through VIII). Anyone think 
    this is doing good dosimetry, when bordering on the 
    boundaries?

7) One should ensure that the dosimeter replacing a former
    dosimeter should be statistically equivalent. In other words, as 
    good as or "better". rationalizing that the radiation mix isn't 
    improtant doesn't cut it. That might satisfy your management, but 
    will it satisfy a jury of your peers? Maybe so, maybe not. 
    However, if you read some previous legal court conclusions, with 
    respect to radiation litigation cases, you will note that the 
    level (degree) of testing a TLD for dose of record, has held up 
    very well. A new dosimeter will need to be able to stand the test 
    of time.

8) Testing a Mean between two dosimeters, i.e., a TLD and an 
    Electronic Dosimeter is OK. However, testing means is not 
    adequate. It is also extremely important to look at individuals 
    .. not collective dose comparisons. It is in the individual 
    evaluation that the accuracy and precision of the systems can be 
    determined.

9) As Bob Flood pointed out, use of a single dosimeter by a large 
    number of individuals is quite different than using a large 
    number of dosimeters by a few individuals. 

Just a few items that one should consider when selecting a dosimeter 
to be used as a dose of record. There are many more, but that would 
take a book!

------------------
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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