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.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
Certain factors or conditions may interfere with the accuracy of a pancreas scan. These factors include, but are not limited to, the following:
Before the procedure
Your doctor will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.
Generally, no prior preparation, such as fasting or sedation, is required prior to a pancreas scan.
Notify the radiologist or technologist if you are allergic to or sensitive to medications, local anesthesia, contrast dyes, iodine, or latex.
If you are pregnant or suspect you may be pregnant, you should notify your doctor.
Based on your medical condition, your doctor may request other specific preparation.
During the procedure
A pancreas scan may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices.
Generally, a pancreas scan follows this process:
You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure.
If you are asked to remove clothing, you will be given a gown to wear.
An intravenous (IV) line will be started in the hand or arm for injection of the radiopeptide.
The radiopeptide will be injected into your vein. The radiopeptide will be allowed to concentrate in the pancreas tissue.
You will be asked to lie still on a scanning table, as any movement may affect the quality of the scan.
The scanner will be placed over the abdomen in order to detect the gamma rays emitted by the radiopeptide in the pancreas tissue.
You may be repositioned during the scan in order to obtain views of all the surfaces of the pancreas.
When the scan has been completed, the IV line will be removed.
While the pancreas scan itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly in the case of a recent injury or invasive procedure such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.
After the procedure
You should move slowly when getting up from the scanner table to avoid any dizziness or lightheadedness from lying flat for the length of the procedure.
You may be instructed to drink plenty of fluids and empty your bladder frequently for about 24 hours after the procedure to help flush the remaining radionuclide from your body.
The IV site will be checked for any signs of redness or swelling. If you notice any pain, redness, and/or swelling at the IV site after you return home following your procedure, you should notify your doctor as this may indicate an infection or other type of reaction.
You may resume your usual diet and activities, unless your doctor advises you differently. Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.