Re: I-131 Patient Rooms & B. Black's Trick

[Ben Vandre <bvandre@post.its.mcw.edu>]

Ok, I talked to Bob Black the RSO at the VA, a microbiologist, and a chemist.

As it turns out two processes are at work.

First, there is a plethora of microorganisms living in a sink's trap.  The
organisms adhear to any crack or surface possible and some of them digest
iodine.  Pouring the KI solution into the sink prior to the patient's
treatment, supplies the organisms with an abundance of nonradioactive iodine
to digest.  By the time the patient starts excreating I-131, the
microorganisms in the trap are saturated with nonradioactive iodine allowing
the I-131 to continue on its trip to the sanitary sewer system.

Trying to kill the organisms, with a strong base for example, also works.
But, it is harder to kill all the microorganisms than is typically thought.
It may take several applications.

Microorganisms are the primary reason Iodine becomes caught in the trap.
This is why a KI solution doesn't work as well on a toilet bowl or other
surfaces.  Less microorganisms live in a toilet bowl because the organisms
are constantly killed off by urine, consider urine's pH.

The second process involves the ionic nature of iodine.  But as many fellow
Radsafers have already noted, the ion exchange process has a MINIMAL EFFECT
so I will only explain it breifly.  Iodine in a solution is an anion which
is attracted to cations.  By filling "cation spaces" that may exist in a
trap or on porcelain services with nonradioactive Iodine's anion, the
radioactive Iodine has nothing to bond to and again continues on its way to
the sanitary sewer system.

End note, I believe there is an article in the most recent Health Physics
Journal concerning Patient Treatment Rooms.  I haven't read it yet so I
can't say if it will help.

I've got to get back to work now.

Ben Vandre
Medical College of Wisconsin
bvandre@post.its.mcw.edu

Disclaimed  Disclaimed  Disclaimed  Blah  Blah  Blah!


At 08:31 AM 2/13/96 -0600, you wrote:
>Our patient load has increased to the point to where we are seeking ways 
>to radiologically release our treatment rooms faster after the patient 
>has been released. We are primarily having problems with the toilet and 
>sink traps. We advise the patient to flush the toilet 3 times after use 
>and to rinse the sink for 30-45 seconds after use.We currently allow 
>Chlorox to remain in the bowl overnight. Is there any other methods we 
>might try or is anyone out there using any chemical means to expedite 
>cleanup. We currently allow Chlorox to remain in the bowl overnight.
>Mark E. Campbell
>Health Physicist Supervisor
>Radiation Safety Division
>University of Alabama at Birmingham
>445 Community Health Services Building
>933 South 19th Street
>Birmingham, AL. 35294-2041
>(205) 934-9345 - FAX (205) 934-7487
>
>