Re: MQSA def'n rad

[Chris Alston <alstonc@odrge.odr.georgetown.edu>]

>Date:         Fri, 14 Nov 1997 12:26:07 -0600
>Reply-To: Medical Physics Mailing List <MEDPHYS@LISTS.WAYNE.EDU>
>Sender: Medical Physics Listserver <medphys@lists.wayne.edu>
>From: William Geisler <geislerw@DGABBY.MFLDCLIN.EDU>
>Subject:      Re: MQSA def'n rad
>To: Multiple recipients of list MEDPHYS <MEDPHYS@LISTS.WAYNE.EDU>
>
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>On Thursday, Nov. 13 1997 "Ira D. Miller" <milleri@connecti.com> wrote:
>
>>By the way has anyone noted the official definition for a rad in the new
>>MQSA.  1 gray = 100 radians (rads) = 114 R
>
>Yes, I saw this too.  However, is this really new?  Is this not just the
old "f-factor" conversion?  I.e., the 0.00876 Gy/R conversion factor for
absorbed dose (multiplied by the ratio of the mass energy absorption coeff
mu|en/density).
>
>As an aside (and given that I currently practice diagnostic physics), I
notice in Khans' _The Physics of Radiation Therapy_ that this factor is .876
rad/R while Johns and Cunninghams gives .873 rad/R.  Which witch is which?
>
>Bill
>
>William R. Geisler, M.S.
>Medical Physicist
>Marshfield Clinic
>1000 N. Oak Ave
>Marshfield, WI 54449
>(715) 389-3826
>FAX:  (715) 387-5240
>email:  geislerw@mfldclin.edu
>