What is a pancreas scan?
A pancreas scan is a specialized radiology procedure used to assess the pancreas for the presence of a specific type of tumor. A pancreas scan is a type of nuclear radiology procedure. This means that a tiny amount of a radioactive substance is used during the procedure to assist in the examination of the pancreas. A pancreas scan may also be used to treat certain malignant tumors of the pancreas.
In many nuclear medicine procedures, the radioactive substance is referred to as a radionuclide. However, the radioactive substance used in a pancreas scan is called a radiopeptide, because the compound to which the radioactive material is attached is a synthetic peptide (an organic compound which is a component of protein). Because tumor cells readily bind with certain peptides, nuclear medicine radiologists have developed highly specific radiopeptides that bind with tumor cells and thus make certain tumors visible with nuclear imaging techniques. In addition, radiopeptides may be used to treat certain types of tumors by using specific therapeutic radioactive substances attached to the radiopeptide.
Once the radiopeptide has bonded with the peptide receptor cells of tumors, the radiopeptide emits a type of radiation, called gamma radiation. The gamma radiation is detected by a scanner, which processes the information into an image of the tumor.
Other related procedures that may be used to diagnose problems of the pancreas include abdominal X-rays, computed tomography (CT scan) of the abdomen or pancreas, or an endoscopic retrograde cholangiopancreatography (ERCP). Please see these procedures for additional information.
Anatomy of the pancreas
The pancreas is an elongated, tapered organ located across the back of the abdomen, behind the stomach. The right side of the organ (called the head) is the widest part of the organ and lies in the curve of the duodenum (the first section of the small intestine). The tapered left side extends slightly upward (called the body of the pancreas) and ends near the spleen (called the tail).
The pancreas is made up of two types of glands:
Exocrine. The exocrine gland secretes digestive enzymes. These enzymes are secreted into a network of ducts that join the main pancreatic duct, which runs the length of the pancreas.
Endocrine. The endocrine gland, which consists of the islets of Langerhans, secretes hormones into the bloodstream.
Functions of the pancreas
The pancreas has digestive and hormonal functions:
The enzymes secreted by the exocrine gland in the pancreas help break down carbohydrates, fats, proteins, and acids in the duodenum. These enzymes travel down the pancreatic duct into the bile duct in an inactive form. When they enter the duodenum, they are activated. The exocrine tissue also secretes bicarbonate to neutralize stomach acid in the duodenum.
The hormones secreted by the endocrine gland in the pancreas are insulin and glucagon (which regulate the level of glucose in the blood), and somatostatin (which prevents the release of the other two hormones).
Reasons for the procedure
A pancreas scan may be performed to screen for primary or metastatic cancer of the pancreas. A pancreas scan may be used to assess response to therapy for pancreatic cancer and/or to monitor the course of the cancer.
There may be other reasons for your doctor to recommend a pancreas scan.
Risks of the procedure
The amount of the radiopeptide injected into your vein for the procedure is small enough that there is no need for precautions against radioactive exposure. The injection of the radiopeptide may cause some slight discomfort. Allergic reactions to the radiopeptide are rare, but may occur.
For some patients, having to lie still on the scanning table for the length of the procedure may cause some discomfort or pain.
Patients who are allergic to or sensitive to medications, contrast dyes, or latex should notify their doctor.
If you are pregnant or suspect that you may be pregnant, you should notify your health care provider due to the risk of injury to the fetus from a pancreas scan. If you are lactating, or breastfeeding, you should notify your health care provider due to the risk of contaminating breast milk with the radiopeptide.