[ RadSafe ] Cl-36 in Nuclear Medicine?

[Siegel, Barry]

I can find no evidence in the medical literature that Cl-36 has ever been used for PET in humans, and I doubt it ever will be with that half life.  Even if only a tiny fraction of the administered activity found its way into a long-lived compartment, the committed dose would be unacceptable.  Moreover, since PET imaging typically requires dosages in the range of 1-20 mCi, the disposal of RAM waste, excreta, etc. would be a significant  regulatory issue.  Almost everything used for imaging in medicine has a half-life under a week (I-131 being a borderline exception).

Barry A. Siegel, M.D.
Division of Nuclear Medicine
Mallinckrodt Institute of Radiology
Washington University School of Medicine
St. Louis, MO

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brennan, Mike (DOH)
Sent: Thursday, July 15, 2010 4:57 PM
To: radsafe at health.phys.iit.edu
Subject: Re: [ RadSafe ] Cl-36 in Nuclear Medicine?

I believe that Cl-36 is used as a source of positrons (Antimatter! It's
not just for Star Trek anymore!).  Positrons are used in Positron
Emission Tomography (PET), which uses the fact that when a positron
encounters an electron they mutually annihilate and produce photons
traveling in exactly opposite directions.  Using some seriously good
detectors and some non-trivial software, the photons can be used to
provide imaging good enough to make your brain explode (which, I
believe, a PET scan could capture for later examination).

As chlorine has a ten day biological half life, the stay time of the
Cl-36 isn't too great (I don't know what amounts are administered).  I
imagine that this could be hurried along by increasing salt and liquid
intake, though as I am not a doctor, I am not prescribing potato chips
and beer as a post-procedure regime.

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of
jearadrat at aol.com
Sent: Thursday, July 15, 2010 2:05 PM
To: radsafe at health.phys.iit.edu
Subject: [ RadSafe ] Cl-36 in Nuclear Medicine?



Good afternoon, all:

In a reqcent company training session, one of my fellow technicians
mentioned that a nuclear medicine application was being developed for
chlorine-36.  Considering the VERY long (3E5 yrs) half-life, what
possible patient application can there be for this?  Or is it possible
some erroneous information is being spread?

Thanks in advance,
John Aperans, RRPT
Clinton, TN USA


P.S. Please be gentle, this is my first post.
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