Fine-needle aspiration biopsy is a procedure used to take a lung tissue sample (a tissue biopsy). The tissue sample is taken from a nodule, abnormal tissue, tumor, or lung mass. First, a CT scan or ultrasound is done. This helps the doctor find the area. Then, a thin needle is passed through the skin of the chest into the nodule, abnormal tissue, tumor, or lung mass. Another CT scan or a chest X-ray is taken to be sure the needle is placed correctly. Once the needle is in place, a small amount of lung tissue is drawn (aspirated) into the needle. The lung tissue sample is then sent for testing.