[ RadSafe ] Re: radsafe Digest, Vol 181, Issue 3

[Dale Boyce]

Measuring the dose rate from a patient with common survey equipment is 
inherently problematic. GM's and scintillators (with the exception of tissue 
equivalent scintillators) is strongly effected by the energy response. As an 
example using the most common GM detectors pancake and 3 inch end window to 
measure dose rate from a patient for either Cs-131 or I-125 prostate implant 
will result in a factor of 3 too high a reading as compared to a tissue 
equivalent scintillator or ion chamber (assuming Cs-137 calibration to dose 
for the GM and scintillator).

Most diagnostic radiopharmaceutical administrations will be 2 mrad/hr or 
less at 1 meter immediately after administration.

Dale


----- Original Message ----- 
From: "Ed Stroud" <estroud at smtpgate.dphe.state.co.us>
To: <radsafe at radlab.nl>; <al at solidsurfacealliance.org>
Sent: Monday, January 26, 2009 6:09 AM
Subject: [ RadSafe ] Re: radsafe Digest, Vol 181, Issue 3


Most cardiac stress tests use Tc-99m with a half-life of 6 hours. However, 
some cardiologists prefer to use a combination of Tc-99m and Tl-201. 
Thallium has a half-life of 73 hours.
-Ed Stroud

>>> <al at solidsurfacealliance.org> 1/23/2009 5:30 PM >>>


Hi All,

I friend of mine had a stress test on Tuesday, heart patient, had some 
stents installed a few weeks back.   About a foot away from his chest, my PM 
1703 Gamma Scintillator was reading over 2,500 uR/hr.   This was Saturday 
night, at least four full days after the procedure.

Is this unusual?  I thought most of those medical isotopes had very short 
half lives.

Thanks,

Al

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