Re: Contaminated Hosp Pipes

[Al Tschaeche <antatnsu@pacbell.net>]

A. Hancock wrote:
> 
> ANY THOUGHTS ON THIS PLEASE:
> 
> Patients receive up to 7.4GBq (200mCi) I-131 for Ca-thyroid radionuclide
> therapy. This is administered on the 6th floor of our hospital.
> 
> Excreted I-131 from these patients passes through cast iron waste pipes
> down the building to the main drain. 90% of the administered activity is
> lost via this waste stream. The pipes pass through occupied work areas to
> reach the main drain.
> 
> Careful monitoring of these pipes, in their associated ducting cupboards,
> has indicated that significant internal contamination builds up within
> the pipes which remains fixed irrespective of the additional flow of
> non-active fluid down the pipes. External doserates in the work areas the
> pipes pass through can exceed 5uGy/hr, and in the direct vicinity of the
> pipes, up to 30uGy/hr, two days after administration of the iodine dose.
> Subsequently these doserates only fall via radioactive decay over the
> following days/weeks.
> 
> What can we do ?
> 
> One school of thought is that the iodine is being bound to "crud" which
> builds up and lines the pipes.
> 
> Another school of thought is that the pipes are internally corroded and
> that the iodine is binding to the corrosion sites.
> 
> We have decided to internally purge one of the pipes, and reassess. If
> the crud theory is correct we may have an answer. If the corrosion theory
> is correct we may only expose more corrosion sites by cleaning, and
> therefore make the matter worse!
> 
> What do you (out there) suggest? N.B. There is no money to replace these
> pipes in the immediate future, or so I'm told.
> 
> FROM:
> Andy H
> a.hancock@cxwms.ac.uk
> Radiation Protection Adviser
> Charing Cross Hosp
> London UK

This looks like another "non-problem" dose wise.  I cannot believe what
I see on radsafe recently.  This plus the guard's clothing plus
conatminated lead, none of which will produce ANY significant dose to
anyone.  By-the-way, in none of these items has the dose to anyone been
estimated. Why do we do something when the benefit from doing it is
unmeasurable????? if any!!!!!  This is NOT radiation protection.  We
aren't protecting anyone from anything.  Why do anything about the
pipes, the guard's clothing or the lead products if there is no
significant dose to anyone?  Sorry, but these three things, and, I
suspect, many others, smack of irrational "radiation protection."  Now,
who will speak first?  Al Tschaeche, CHP antatnsu@pacbell.net