Joy,
I had this procedure done about 9 months ago. My head and neck CT turned up a suspicious spot on my lung so they did a chest and abdomen CT scan which ultimately indicated an enlarged lymph node in my abdomen. They did a CT-guided fine needle aspiration to check the node for cancerous cells.

Assuming the head and neck procedure is pretty simimilar to the abdominal one, they put you in the CT machine, roll you under the imaging head until the section of your head and neck appears on the monitor. Then, they start to insert the needle and constantly take images to make sure that the needle is on target and not near anything that could cause problems (like arteries). The procedure is relatively painless. Of course no one likes needles but it is roughly comparable to getting a needle vacination, although the needle is stuck in you for a longer period of time.

Once the lymph node is penetrated, they will draw lymphatic fluid from the node, add stain and then test it under a microsope for cancer. At my procedure, they took the fluid and told me within 5 minutes of drawing it, that the preliminary results were good but that it needed to be confirmed by the pathologist doing a more thorough assessment.

With a local anaesthetic, the whole procedure lasted about 25 minutes and was relatively painless, orders of magnitude easier than radiation. Good luck with your test. - Sheldon.