An endoscopic ultrasound (EUS) is like an endoscopy, but the endoscope has an ultrasound probe on the tip. The probe uses sound waves to make pictures of organs in the body.
It is usually used to measure the cancer and to see if it has spread (staging). This includes looking at nearby lymph nodes, and taking tissue samples (biopsies) if needed. It can also be used to help diagnose some types of cancer.
Your doctor or nurse will explain what an endoscopic ultrasound is and what to expect. They will tell you if you need to do anything beforehand. For example, if you should not eat or drink for a period of time before the procedure.
The doctor will give you a sedative to help you relax. They also spray a local anaesthetic on to the back of your throat to numb it.
The ultrasound also helps guide the specialist doctor to the area they want to take samples of tissue (biopsies) from.