A choline C-11 PET scan looks for cancer cells and other fast-growing cells in the body. Most often, it's done to find prostate cancer that comes back after treatment, which is sometimes called recurrent prostate cancer. A choline C-11 PET scan might be used if other imaging tests haven't been helpful in finding the cancer.

Researchers also are studying other ways to use choline C-11 PET scans. This test has shown promise in finding overactive parathyroid glands. Parathyroid glands are found behind the thyroid at the bottom of the neck. They make parathyroid hormone, which helps keep the right balance of calcium in the body. Sometimes one or more of the glands make too much parathyroid hormone. This condition is called hyperparathyroidism. Studies show that choline C-11 PET scans might help find overactive parathyroid glands when other imaging tests can't.

A choline C-11 PET scan is a safe imaging test. Like all tests, it has some risks. These include:

• A mild reaction at the place where the radioactive tracer goes into the arm.
• Allergic reaction to the radioactive tracer.
• Exposure to radiation from the tracer.
• False-negative result. This can happen if cancer is present but the test doesn't detect it.
• False-positive result. This can happen if the scan detects something that looks like cancer, but further testing finds that it isn't cancer.

If your healthcare team gives you instructions to help you prepare for a choline C-11 PET scan, follow them carefully. You may be asked to:

• Stop eating for a few hours before the test.
• Drink plenty of liquids, such as water, for a few hours before the test.

During a choline C-11 PET scan, you receive an injection in your arm and then have an imaging test.

A healthcare professional injects a radioactive tracer into a vein in your arm. The tracer is a radioactive form of the vitamin choline.

After the injection, you'll have a positron emission tomography scan, also called a PET scan. During the scan you lie on a table. The table slowly moves into the center of the imaging machine. The machine takes images of the body.

Often the same machine does a CT scan at the same time. Sometimes a choline C-11 PET scan is done by a machine that also makes MRI pictures.

Once the imaging tests are complete, you can go about your day. Your healthcare team might recommend that you empty your bladder as soon as you can after the test. This helps clear the radioactive tracer from the body.

Ask your healthcare team when you can expect to know the results of your choline C-11 PET scan. This imaging test shows places in the body that absorb the radioactive tracer. Places that absorb the tracer may be cancer or another condition that causes cells to grow quickly. Sometimes other imaging tests or procedures might be needed to be sure.