Your doctor will slide the ultrasound probe back and forth over your thyroid gland to determine precisely which area to biopsy. An injection of an anesthetic solution (lidocaine) is usually used to numb the skin first. You will feel a “pinch” and “burn” while the anesthetic begins to work. Using the ultrasound to guide the needle tip, your doctor then inserts a thin needle into your thyroid gland and removes a small amount of thyroid cells and fluid through the needle.
After each pass with the needle, the material from your thyroid gland is placed on a glass microscope slide and sent to the cytology laboratory for examination. Your doctor may perform 4-6 passes of the thyroid nodule to get an adequate specimen. During a needle biopsy, you may feel pressure or a brief, sharp pain in your neck as the needle enters your thyroid gland. Try not to swallow, cough, or make any sudden movements when the needle is in your neck to prevent injury. You do not need to hold your breath during the biopsy, but stay calm and still.