Re: I-131 Air Sampling

[Keith Varnado <kvarnado@premier1.premier.net>]

At 09:47 AM 6/28/96 -0500, you wrote:
>
>     RadSafe,
>     
>     I am with the Rad. Safety Div. in the Occ. & Env. Safety Office at 
>     Duke Univ.  I am working on a radioiodine (I-131) project looking at 
>     the therapeutic use of I-131 in the hospitals.  One of the aspects of 
>     the project will be air sampling in patient rooms after the patient 
>     has been dosed.
>     
>     At this point in time I am considering going with a low vol. sampler 
>     (around 2 lpm) using activated charcoal tubes in conjunction with HEPA 
>     filters.  Does this sound like a good idea (or not)?  
>     
>     I would graciously welcome information/advice anyone might have 
>     regarding this type of air sampling (i.e. equipment use, flow rates, 
>     sample times, and any other suggestions)
>     
>     My e-mail address is brind002@mc.duke.edu
>     
>     Thanks,
>     
>     Jim Brindle
>
>

Jim,

There are several companies that market air samplers, filters,
supplies, etc.. that will likely assist you. Radeco and F&J 
are two I'm familiar with. My recommendation though would be 
a low volume air sampler which uses a combination filter holder. 
The holder contains a 2" particulate filter and a standard 
activated charcoal cartridge (I would stay away from silver 
zeolite, it's expensive). Use a flow rate of about 2 scfm, 
this gives you a charcoal iodine collection efficiency of 
about 95%. Depending on the form of iodine you will be using, 
you may see activity on the filter paper(I've seen up to 10% 
of of the total iodine activity on the filter paper). Depending 
on the counting system you have, a sampling time of 20-30 minutes 
should get you close to the MDA you are looking for.

Samplers using carbon vane vacuum pumps are generally low 
maintenance, rugged, and relatively inexpensive. They do make 
noise though. If you attach a short length of tygon tubing to 
the sample holder, you can move the sampler so it will be less 
noisy in the patient room.

2 lpm is way too low of a flow for what I think you may want. 
Also, a HEPA filter will not do you much good. If I can provide 
you any more info, let me know.



	Keith Varnado, CHP
	kvarnado@premier1.premier.net