Re: Sentinel Node Studies

["Mike Bohan" <mike.bohan@yale.edu>]

        Reply to:   RE>Sentinel Node Studies

Hi Betty,

I've buried my response in the body of your post.  I've sent it to the list
because I feel that the Medical RSO's out there may want to add their
experiences and $0.02 worth.  I figure Melissa will let me know if I am
talking too much!

P.S. - Thanks for all for the responses to my post on syringes!

<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><
Michael J. Bohan, RSO   |  e-mail: mike.bohan@yale.edu
Yale-New Haven Hospital |    Tele: (203) 785-2950
Radiological Physics    |     FAX: (203) 737-4252
20 York St. - WWW 204   |    As usual, everything I say may be plausibly
New Haven, CT    06504  |    denied at my employer's convenience ...
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--------------------------------------
Date: 12/03/97 9:45 AM
To: Mike Bohan
From: radsafe@romulus.ehs.uiuc.edu
Our hospital has recently started lymph node mapping for melanomas
using Tc-99 sulfur colloid. They will soon start lymph node mapping for
breast tumors.  The dose for the melanoma study is 500 microcuries, and
1 millicurie for the breast study. The Tc-99m sulfur colloid is injected
adjacent to the tumor site. There is a delay of about 2 to 4 hours from
the time of the dose until the patient goes for surgery. The surgeon
locates the sentinel node with a "gamma probe".  Sometimes the breast
tumor (site of dose) will be removed and sent to pathology along with
the lymph nodes.
	My questions to radsafers are:  

(1) Who do you train and how extensively?

I would train the Surgical Staff, the O.R. Staff and the Path. Staff.  I would
give them basic rad. safety training, time, distance, shielding and
contamination control supplemented with a description of the procedure.  I
would make sure that they understood that this happens routinely with surgical
patients who have received recent diagnostic nuc. med. studies.  The external
radiation levels are small and they already almost know how to limit
contamination because of the standard "Universal Precautions" they all have
come to know and love.  %^)
  
(2) Are the tissue samples labeled to alert pathology?

If the tissue specimens are known to be contaminated, they should be labeled
so the Path. people will be properly informed.  We had a similar problem with
I-125 seed implants a few years ago.  Primarily head & neck I-125 implant
patients were failing and being reoperated on after ~ 6 months.  Tissue
specimens containing decayed but still active seeds were showing up at the
Path. Lab.  We installed an alarming radiation detector and required ALL
tissue specimens to be surveyed upon receipt.  This alerted them to all
significantly contaminated samples from Nuc. Med as well as Brachytherapy.  It
was tough at first, but we have developed a relationship and they know that
were are available to help if they find something.  However, they still
insisted that known radioactive specimens be labeled despite our survey
program!  

(3) What precautions do you advise for the tissue handlers in pathology?

Pretty much standard "Universal Precautions".  We ask them to Faxitron (X-ray)
tissue specimens (to determine if the radiation source is from I-125 or Pd-103
seeds or from Nuc. Med.


(4) Do you advise them to wait 24 hours or longer before processing the
samples?  

No.  The radiation levels from the tissue specimens are not that large and the
surgeons are usually back in the O.R. demanding an immediate read so they know
when to stop the lymph node dissection.

(5) After processing, the tissue specimens are stored for several weeks - do
you require locking and labeling the freezer where the tissue is stored?

No.  The radioactivity levels are are low enough and the half-life short
enough that this should not be considered a problem.  The security of the
specimen storage area should be good enough.  The radiation hazard is the
least of the "real" biological/chemical concerns for these materials. 

(6) Is the removed tissue considered patient excreta or radioactive waste?

I would consider it excreta.  By the time is is disposed, it will have greatly
exceeded 10 half-lives and what about the "unknown" specimens which are
routinely handled from patients who have had diagnostic studies before
surgery?  Many of these cases involve Ga-67 with a 3 day half-life.  Our only
exception, at this time, are specimens containing I-125 or Pd-103 seeds.  We
require that these specimens be returned to the RSO for decay-in-storage after
they are no longer of use to the path. dept.
 
(7)	I have trouble stating that "there is no significant hazard associated
with handling these specimens", then giving extensive instructions on
how to lower handlers' dose (as in the radiation safety training from the
protocol of one multi-center study).  I've found that this type of
instruction causes confusion and sounds like double-talk.

Unfortunately, we're forced to do the double-talk by the regulations.  Your
license requires that "ALL" individuals who frequent areas where licensed
materials are used must be trained appropriately for their involvement in the
materials use.  The most important thing to do is to be there for them and
support their needs until they become comfortable with the new program.  Once
you develop this rapport, after a lot of initial work, you will find that most
individuals will understand the issues and comply with the protocols set up.

 
	Please respond directly to me unless you think this is of general
interest for radsafe.  Thanks!
 
Betty Schwab 
bschwab@gems.vcu.edu
Virginia Commonwealth University/Medical College of Virginia Hospitals