To prepare a phantom lesion, cut a six by six inch piece of cardboard to serve as the base plate. Cover the base plate with a layer of caulk half an inch thick. Then cut a piece of banana two and a half inches long and press it gently into the caulk.
The banana serves as the phantom lesion core completely Embed the core in caulk without trapping air bubbles. Cover the core with a piece of plastic wrap and shape it into a smooth mound. Let the caulk mount cure in a warm place after the caulk is firm and cured.
Peel off the plastic wrap practice FNA proficiency to retrieve specimen from the banana core and practice smear preparation. I am Dr.Vino from Cytopathology Division at the Department of Pathology at Medical College of Wisconsin. And I'm Dr.George Varszegi, a Cytopathology fellow in the same department.
Today we'll be demonstrating a procedure to prepare a phantom lesion for practicing proficiency in FNAV procedure performance by using easily available and simple tools and material. We generally use this technique to introduce cytopathology fellows and pathology residents to the final aspirate biopsy procedure. Later on in their training, fellows and residents will hone their skills by performing financial aspirate on clinically palpable lesions under the supervision of faculty.
So let's get started. Prepare the phantom lesion one or two days before your anticipated FNAB practice session. Before you start, have ready on the bench, a piece of cardboard, a caulking gun, an unpeeled banana, and saran wrap.
The first step in preparing a phantom lesion is to cut a six by six inch piece of cardboard to serve as the base plate. Next, cut a segment of banana approximately two inches long, which will serve as the phantom lesion core. After the phantom lesion core is ready, take a caulking gun and spread about a half inch thick layer of caulk onto the base plate.
Lightly press the phantom lesion core into the wet caulk. Now add more caulk over the phantom lesion core to completely embed it. Be careful not to trap air bubbles in the caulk wearing gloves.
Spread the caulk over the phantom lesion core by hand to make sure it is completely surrounded. Now cover the mound with a six by six inch piece of plastic wrap and sculpt the mound into a smooth convex shape. Put the caulk mound in a warm place to cure for six to eight hours longer than the curing time suggested for your particular brand of caulk.
The caulk sets when exposed to air. You can leave the mound at room temperature above 60 degrees Fahrenheit or incubate at 37 degrees Celsius to hasten the curing. After curing, the caulk is firm and you can easily peel off the plastic wrap.
The FNA phantom lesion is now ready to use for practicing the FNA procedure. Now that you have prepared your phantom lesion and it has cured, you can use it to practice the FNAB procedure. Here we are using the tissue harvester with functional valve, but you can use any FNA system in brief.
The THFB consists of a needle to pierce the specimen, a needle hub to collect aspirated material, a syringe to control the pressure inside the device and a valve to connect and disconnect the needle hub from the syringe. Begin by preparing the FNA assembly with the valve connecting the needle hub to the syringe closed. Now pull out the syringe piston to create a vacuum within the syringe barrel.
Then insert the needle tip into the lesion. Open the valve to connect the needle hub to the vacuum in the syringe barrel. The vacuum draws material from the lesion into the needle and into the needle hub.
Move the needle to and fro in the lesion to aspirate a representative sample of cellular components. Maintaining the vacuum sample different areas of the lesion by inserting the needle into the lesion in different directions. When you are done sampling, rotate the valve to disconnect the vacuum in the syringe barrel and equalize the pressure with exterior conditions by opening the valve.
Next, rotate the valve to disconnect from the exterior and the syringe barrel. Remove the needle from the lesion with the valve closed. Keeping the valve closed maintains slight negative pressure in the hub end, and prevents the specimen from draining back into the lesion by capillary action.
Comparable to pipetting phenomenon, your tissue sample is now safe in the needle hub. Once you've taken the needle out of the dislodge, the aspirated content onto the glass slide to prepare a direct smear. Once you have dislodged a drop of aspirate onto your slide, you can spread it using a variety of methods depending on the nature of the aspirate, we usually spread the sample between two slides using the method shown here.
Should an actual specimen be diluted with blood, drain away the excess blood by tilting the slide before placing the second glass slide on top. If the aspirate is predominantly a suspension without micro fragments, such as from lymphoproliferative lesions, it can be spread using the ribbing method where the edge of one slide is used to create a rib like set of smears on another slide, or the spreading method can be used where one slide can be used to create a film on a second slide. Once you have prepared the smears, you can process and fix them in a variety of ways.
For different staining methods, the best approach is to air dry all the smears rapidly within one to two minutes. The drying of the thicker and more wet smears may be expedited by moving the slides sideways in air or preferably with a hairdryer or handheld battery operated portable fan. When using a fan, be careful to prevent aerosolization, especially for lesions expected to be infected once the smears have dried, stain them as appropriate for your experiments.
Here we are demonstrating staining of air dried smear with D quick stain, which is one of the romanowski stains for timings. Follow manufacturer's instructions. We find that air drying greatly improves the clarity of staining as shown in this example of pap stained smears.
Analysis of these initial stains will determine additional tests you may want to perform such as elective cell block electron microscopy, microbiology cultures, or others. Successful completion of phantom lesion will allow proper aspiration of lesion material, in this case, pasty vegetable material from banana. This material can be spread on the glass slides to practice smearing and staining.
So we've just shown you how to prepare a phantom lesion for practicing FNAB proficiency. While performing this experiment, it is important to remember that you should prepare the phantom lesion at least 36 hours prior to the proficiency testing session because caulking gel required some time for solidification. Another important point is application of vacuum and release of vacuum in a proper sequence to achieve optimal material of aspirate material while performing the FNAV procedure.
So that's it. Thanks for watching and good luck practicing And thanks a lot.
