Endobronchial ultrasound (EBUS) is a minimally invasive but highly effective procedure used to diagnose lung cancer, infections, and other diseases causing enlarged lymph nodes in the chest. The tool used is a flexible tube that goes into your mouth, and then into your windpipe and lungs. At the end of the tube is a small video camera that takes pictures of your lungs and nearby areas. The pictures can help locate and evaluate places on your lung previously seen on X-rays or scans that need a closer look.