Re: roentgen to rad factor

[photcoef <photcoef@tiac.net>]

Roentgen is a unit of radiation intensity.
rad is a unit of deposited dose and depends on the absorber.
You can calculate the deposited dose (in rad or other units) for any
intensity (in Roentgen or other units) with the PC program PHOTCOEF:
www.photcoef.com

Paul Kehler
photcoef@aol.com
 
At 05:40 PM 11/14/97 -0600, you wrote:
>>X-Sender: viru@therad
>>Date:         Fri, 14 Nov 1997 14:55:53 -0600
>>Reply-To: Medical Physics Mailing List <MEDPHYS@LISTS.WAYNE.EDU>
>>Sender: Medical Physics Listserver <medphys@lists.wayne.edu>
>>From: Ramasamy Virudachalam <viru@THERAD.RPSLMC.EDU>
>>Subject:      Re: roentgen to rad factor
>>To: Multiple recipients of list MEDPHYS <MEDPHYS@LISTS.WAYNE.EDU>
>>
>>
>>         ** Mail from Medphys Listserver **
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>>
>>>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,
>>The correct factor is 0.876 rad/R.
>>The  difference you observed between the values reported in Kahns and Johns
>>books stems from a change in W/e from 33.85 eV/ion pair to 33.97 eV/ion
>>pair. For details refer to Attix's book on Introduction to Radiological
>>physics and Radiation Dosimetry, p72.
>>
>>
>>R.G. Virudachalam, Ph.D.
>>Rush Pres. St. Luke's Med. Ctr., Chicago
>>312-942-5751
>>
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