Re: Rads/rems (formerly radiographer "overexposure")

["Jim Hoerner" <jim_hoerner@HOTMAIL.COM>]

>From: Fischer, Karl (NIH/OD/ORS) [mailto:fischerk@o...]

>Sent: Tuesday, July 29, 2003 11:16 AM

>To: 'radsafe@list.vanderbilt.edu'

>Subject: Rads/rems (formerly radiographer "overexposure")

>

>

>Regarding the usage of rads/rems for high doses, Paul Frame posted an

>informative response back in 1998 (courtesy of the RadSafe archives):

>

>**********

>

>ICRP 60 p114

>

>"The quality factor is applicable only for stochastic effects in the dose

>range up to tens of mGy."

>

>ICRU 51 p6

>

>"The quantity dose equivalent is defined for routine radiation-protection

>applications. It should not be used in numerical assessment of high level

>exposures, for example in radiation accidents."

>

>NCRP 91 p 11

>

>regarding the quality factor Q  "it is applicable at low doses for the

>biological effects of primary concern i.e. cancer induction and severe

>genetic defects. Q is only to be used at low absorbed doses in the range

>of the annual radiation protection limits and not for the high doses that

>might occur in accident situations."

>

>In other words, there is no clear answer.

>

>Paul Frame



Paul, thank you for this great information I was unaware of.  Can you or 

anyone else elaborate?  What does one do beyond 10 Rad?  Are 200 Rad of 

gammas and neutrons equivalent?  I suspect not.



John J., I read your post.  I am confused.  Not by what you wrote; but by 

the apparent contradiction that I see.  If health effects at low doses are 

extrapolated from high doses (~10 Rad and up), how can the Q factor not 

apply at high doses as well?



Please help me to understand this.



Thanks,

Jim





--

Hold the door for the stranger behind you. When the driver a half-car-length 

in front of you signals to get over, slow down. Smile and say "hi" to the 

folks you pass on the sidewalk. Give blood. Volunteer.



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