James Reese
ERS Solutions, Inc.
Health Physicist
(916)
689-2680
(916) 689-6270 fax
james.reese@worldnet.att.net
-----Original Message-----
From: Coogen, Michael [mailto:michael_coogen@hq.dla.mil]
Sent: Tuesday, April 09, 2002 4:29 AM
To: James Reese (james.reese@worldnet.att.net)
Subject: FW: AssistanceJim: Can you post this on the radsafe wizard net for me. I would greatly appreciate it.
mike
-----Original Message-----
From: Coogen, Michael
Sent: Tuesday, April 09, 2002 7:19 AM
To: 'Majordomo@list.vanderbilt.edu'
Subject: Assistance
Importance: HighI have a very dear friend whose wife has been diagnosed with adenocarcinoma of the breast. The radiation therapist is using a linear accelerator that produces a 6 MEV photon. Looking at Figure 5.3, page 129, in
the RHH, June 84 edition, which is for water absorption (it's the closest graph that is comparative for tissue), and using the I=Ioe-(u/p)(p)(t) equation, I calculate that 0.8 of the photons pass right on through the breast. So I
ask why use such high energy photons when most of them are not absorbed. Then looking at the same graph for Compton scattering, at 6 MEV, the scattering calculates to be only 7%. At 180 centigrays (rads/day), I conclude that they need the very high energy photon to minimize compton scattering to the rest of her body. I also suspect that the cone created by the scattered photons is less as the energy goes up. Am I right with these assumptions?
Can anyone shed some light on the type of therapy?
Michael Coogen