Saturday, February 16, 2013

Frozen Sections

Last Sunday we had our first frozen section lab.  Frozen sections are a big part of the PA’s duties.  I've heard people say it is one of their favorite parts about being a PA, but right now it seems a little daunting.   The frozen section is an intraoperative procedure. Since the patient is still on the table in the OR, the pathologists’ assistant has to work fast.  The CAP regulations say that frozen section procedures must be done in 20 minutes.  This includes receipt, accessioning, examination, any inking or special procedures, sign out, and call in to the surgeon.  Therefore the duties that the PA performs must be completed in 7 minutes.  

Here is a description of the PA’s duties (I’ll try to make it as least technical as possible):

Once we receive the specimen we select the tissue that we will use for the frozen section (no necrotic tissue, no normal tissue, we want to demonstrate as much information as possible in 1-2 slides). We ink the margins if necessary and then begin our frozen section procedure.  The frozen section procedure takes place in the cryostat, a chamber that is at least -20°C.  

The tissue is placed on a chuck and surrounded by OCT (essentially a goo that freezes). 

The chuck is put into the head of the microtome  and then we turn the wheel on the side of the cryostat to start taking our sections.

Chuck and selected tissue on microtome

Turning the wheel moves the microtome closer to the knife blade. Each advancement of the wheel cuts a 5 micron section of tissue (this is adjustable, but for our purposes we will keep it at 5 microns). Once it looks like the whole face of the tissue is shown, we use a brush to pull the section away from the block to place it on a slide.

Using the brush to remove the section
The tricky part with this step is getting the section to be smooth so that the tissue doesn’t fold up on itself.  Once the section is on the slide we fix it in alcohol and stain it so that specific components can be seen easily by the pathologist when looking through the microscope.

And that is essentially the frozen section! Can you imagine doing all of that in only 7 minutes? 

During our lab we practiced on pieces of hotdogs.  I was very slow at first, but I started to get the hang of it after a couple of tries.  We didn’t time ourselves, but I’m sure I’m no where near the 7 minute limit.  But with some more practice and many hotdogs later I should have the hang of it!

*These pictures are not my own, they were obtained from google.

On a non related note, my grandparents sent me a card for Valentine’s day with this drawn on it: 

My grandma did a great job and I thought it was adorable!

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