Typically, 3 to 6 fiducial markers are placed around a tumor during an outpatient procedure called endoscopic ultrasound (EUS)
. A thin, flexible tube (endoscope) is inserted through the mouth, down the esophagus, past the stomach and into the pancreas. A thin needle is inserted through the tube into the pancreatic tumor to place the fiducial markers. The endoscope contains a tiny camera, which transmits pictures to a monitor so a doctor can see inside as the markers are placed.
The markers are the size of a grain of rice and can sometimes be placed by a thin needle inserted through the skin. In this case, a doctor uses a CT (computed tomography) scan to help guide the needle and markers to the right spots.
You must wait a week or so after having markers placed before beginning radiation therapy.