Re: "minimal risk"?

[andrew_mcewan@nrl.moh.govt.nz]

Sandy Everage wrote

"I am hoping that someone can help our Institutional Review Board (Human
Subjects Committee) in deciding what constitutes more than "minimal
risk" from x-ray exposure.  Is there a maximum mrad amount that could be
considered "minimal risk", in which research proposals could go through
expedited review, or should all research involving radiation require
full-committee review?
Thanks for your help."



There may not be anything established in a formal way but a pragmatic approach
      would be to recognise that risks of around 1:million per year are commonly
      disregarded, even when involuntary.  Using the ICRP fatality risk
      coefficient this corresponds to a dose of 20 microsieverts (2 mrem) per
      year, and a value around this magnitude has widely been regarded as "de
      minimis" or "below regulatory concern".



Andrew McEwan
_________________________
Andrew C McEwan PhD
National Radiation Laboratory
PO Box 25-099
Christchurch, New Zealand

Ph 64 3 366 5059
Fax 64 3 366 1156
Andrew_McEwan@nrl.moh.govt.nz



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