RE: Sterilization for I-192 Seeds.

[VERNIG.PETER@FORUM.VA.GOV]

{Original Msg: 'Re: Sterilization of Ir-192 Seeds in Nylon Tubing' from <root@romulus.ehs.uiuc.edu>
{
{     Bleach (Sodium Hyperchlorite) is not an acceptable procedure for 
{     sterilization of any items for medical use.  Usually ethylene oxide is 
{     the standard procedure for non-metalic items.  This is ususally 
{     accomplished with a gas sterilization autoclave.  You might possibly 
{     consider steam autoclaving sterilization.  I have steam sterilized 
{     nylon tubing using steam autoclaving.  I would recommend that you 
{     determine what pressure, temperature is need to render the HIV virus 
{     inactive.  There are maybe other chemical available to perform 
{     chemical sterilization, however, continue use of these products will 
{     eventually degrade the nylon tubing.  Steam autoclave would be a 
{     possible alternative, however, continue use of this method will 
{     eventually degrade the tubing also.  Any major medical facility should 
{     have a ethylene oxide autoclave.  This is usually an essential 
{     standard equipment necessary to support operating room suites.
{     
{     mike coogen sends
{
{
{______________________________ Reply Separator _________________________________
{Subject: Sterilization of Ir-192 Seeds in Nylon Tubing
{Author:  radsafe@romulus.ehs.uiuc.edu at hq2ccgw
{Date:    8/29/95 10:07 AM
{
{
{Has anyone ever had to sterilize nylon tubing containing Ir-192 seeds for an 
{HIV positive patient?  Our Radiation Oncology dept. wants to use bleach, but 
{there is concern that it will degrade the nylon.  The company who 
{manufactured the seeds says that they should only use gas sterilization, but 
{for several reasons this is not currently an option.
{     
{Any information would be greatly appreciated.
{     
{     
{ ------------------------------------------------------------------------- 
{ Melanie Byers, Health Physicist   Vanderbilt Univ. Institutional Safety
{byersmm@ctrvax.vanderbilt.edu     Radiation Safety Section
{ (615)322-2057 (phone)             Nashville, TN 
{ ------------------------------------------------------------------------- 
{ This is my opinion only and does not necessarily reflect my employer's.
{     
{
 
 
I'm a little confused here.  To implant seeds in an HIV patient.  I would
think the standard gas sterilization would be what you should use. 
Doesn't really matter if it will inactivate HIV virus does it?
 
When the implant is removed, you of course want to insure that it doesn't
carry active HIV virus whether you keep the ribbons and potentially reuse
them at your facility or return them to the vendor who might resell them
if the activity is appropriate.
 
Suitable sterilization for an implant might or might not inactivate [kill]
HIV.  My understanding is that bleach is an accepted means of deactivating
HIV.  Then the question becomes will the bleach treatment compromize the
the Ir-192 seed/ribbon making the loss of a seed more likely.  While it
seems doubtful that a treatment of bleach would cause the plastic [is it
nylon?] to deteriorate that much, it is probably better to test the assump-
tion.  Another possibility is to just to not rejuse the seeds or not return
them to the vendor until they have decayed past usefulness.  You'd probably
still want to use bleach or some method to insure inactivation of the 
virus.
My recollection is that the seeds are on the order of $10 or 20 each and
it would not be prohibitively expensive to not reuse them after the HIV
patient.
 
We have a virus/HIV lab here and one of the researcher has written a
paper or two on lab practices in deactivation.  But I doubt he knows
for sure whether bleach will degrade the plastic of the ribbon.
It seems like this is a material science question.  To start, you need
to know what the plastic is.
 
 
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