[ RadSafe ] Fwd: Stolen cobalt-60 found in Mexico; curious thieves likely doomed

[Chris Alston]

Dan

I think that you are thinking of a radiocesium machine, like an
irradiator.  Cobalt sources in teletherapeutic machines are usually
changed at < 1 t1/2 (5 y).  You want to treat a pt as fast as
possible, for a number of reasons, including minimizing pt motion and
discomfort, and the number of pts you can treat in a day.  Going from,
e.g., delivery of a daily treatment fraction that takes 0.5 h to one
which takes 1.0 h is a big deal in a busy clinic.

Of course, the clinic might have shut down many years ago, and the
machine is only now being "decommissioned".  That is basically how a
number of ugly incidents have occurred.

Cheers
cja
---------- Forwarded message ----------
From: Dan McCarn <hotgreenchile at gmail.com>
Date: Thu, Dec 5, 2013 at 3:03 PM
Subject: Re: [ RadSafe ] Stolen cobalt-60 found in Mexico; curious
thieves likely doomed
To: "The International Radiation Protection (Health Physics) Mailing
List" <radsafe at health.phys.iit.edu>Dear Group:
If this is an old radio teletherapy source heading toward disposal, then
the actual activity (assuming about 30 years of use) would be less than 1/6
the labeled activity - so perhaps 500 Ci might be more accurate.
Thoughts?
Dan ii