PET/Nuclear Medicine

What is a bone scan?

A bone scan is a special test that allows your doctor to examine your bones in detail. It can help your doctor find out what is causing pain in a bone, or it can help him or her study breaks or tumors in the bones. Pictures are taken over your entire body, although in many cases only one area is studied in detail. Your bone scan pictures will be compared with regular X-rays to get the most information possible out of the study.

What happens during this test?

First, a radioactive substance is injected into a vein in your arm. This will feel like a pin-prick—like when you have blood drawn. You will not feel any other effects of this injection. The substance travels through the blood, and eventually into the bones. This makes the bones visible on the scan.

The bone scan itself is done about three hours after the injection. It usually takes about 30 to 60 minutes. For most bone scans, you will lie on a stretcher or table with the camera above or below you. Many pictures may be taken, or the camera may move slowly down the length of your body.

Is any special preparation needed?

No special preparation is required. However, after you receive the injection, you will be asked to drink plenty of fluids while you are waiting for your scan. You can drink any fluid you like (non-alcoholic), and you should go to the bathroom to urinate as much as you can during this period. This helps clear the radioactive substance from your soft tissue, enabling us to see the bones more clearly.

How do I get results?

A doctor from nuclear medicine will review the results and discuss them with your doctor. Your doctor will explain the results to you.

How safe is this test?

Nuclear medicine procedures are very safe. Your body can eliminate the radioactive materials that are used very quickly. The radiation dose from this test is about 0.53 rem. See the Safety section for a further discussion about safety.

Overview

A Cardiac Perfusion scan is a test that helps your doctor see if you have coronary artery disease, which is a narrowing of the blood vessels that supply oxygen to the heart muscle. If the heart muscle doesn't get enough oxygen, it can cause chest pain or angina. Because angina typically occurs during exercise, we often do this test with you walking on a treadmill.

During this test, we use a radioactive material to take pictures of the heart. The substance is injected into your blood and travels to the heart muscle through the coronary arteries. We then take pictures of your heart, which will help your doctor decide if you have coronary artery disease.

How do I prepare for this test?

• Do not eat or drink anything containing caffeine for 12 hours before this test. Many decaffeinated drinks are also not allowed. For example, do not consume:
• Coffee: Regular or decaffeinated, any variety
• Tea: Regular or decaffeinated, any variety
• Soft Drinks: Regular or decaffeinated, any variety, including Cola, Dr. Pepper, Mountain Dew, Tab, Mellow Yellow, and Pibb Xtra
• Foods: Cocoa, chocolate
• Over-the-Counter Medicines: Anacin, Excedrin, NoDoz
• Prescribed Medications: Cafergot (all forms), Darvon Compound, Fiorinal, Synalog DC, Wigraine (all forms)
• Do not smoke for two hours before this test.
• Do not eat or drink anything except water for two hours before this test.

May I take my medication?

• You may be asked to decrease or stop certain medicines for this test. Follow your doctor's instructions regarding medication. Do not stop your medication unless your doctor tells you to. You should start all your medicines again after the test is over. Please bring a complete listing of all your medicines with you.
• If you are a diabetic and take insulin or another diabetes medication, please check with your doctor for advice regarding doses before and after this test. Please bring your insulin or oral diabetes medicine to the hospital so you can take the dose recommended by your doctor.

What should I wear?

Please wear comfortable clothes that break at the waist (a shirt or blouse) and flat walking shoes or sneakers. Sneakers are strongly recommended. Electrodes will be placed on your chest so that your heart can be monitored during exercise. Women must remove their bras for the procedure. If you wear a particularly large or small clothing size, please bring your own T-shirt and pants. Comfortable clothing will make things easier for you as you exercise during your test.

What happens during this test?

There are three parts to the test: Taking pictures, exercising, and taking more pictures.

1. For the first part of the test, we will put an intravenous (IV) line in your arm. This will feel like a pin-prick, like when you have blood drawn. The radioactive material is then injected through the IV. You will not feel anything from this injection. We will wait approximately 45 minutes while the radioactive material circulates in your body. Then, while you are seated in a specialized camera designed for cardiac imaging, we will take pictures of your heart with a special camera for about 15 minutes.
2. For the second part of the test, you will exercise by walking on a treadmill. Your heart will be monitored with an EKG, and we will take your blood pressure many times during this part of the test. A radioactive material will be injected into the IV about 1 minute before you stop exercising. If you are unable to exercise on a treadmill, or are unable to reach your target heart rate on the treadmill, a medicine will be used to exert the same physiologic effect on your heart that exercise has. You will not feel anything when the radioactive material is injected. We will again wait a short time while the radioactive material circulates in your bloodstream.
3. The third part of the test is taking more pictures. You will sit down as before and the camera will take pictures for about 15 minutes.

How long will the test take?

The test takes a total of three to four hours.

After The Exam

A doctor from nuclear medicine will provide the results of this test to your doctor. Your doctor will put together the results of this test and your other tests and then will explain the meaning of these results to you. 

All the pictures that result from the Cardiac Perfusion exam are cataloged and stored as digital images. These are then displayed on specialized high-resolution video monitors and interpreted by the nuclear medicine physician.

How safe is this test?

Nuclear medicine procedures are very safe. Your body can eliminate the radioactive materials that are used very quickly.

The radiation dose from this test is about 1.17 rem.

What is a parathyroid scan?

Why am I having a parathyroid scan?

What preparation is needed for this test?

How is a parathyroid scan performed?

How will I find out the results of my scan?

How safe is this test?

Overview

Beth Israel Deaconess Department of Radiology installed the first hybrid PET/CT scanner in the state of Massachusetts in April 2003. This technology allows the acquisition of images that show both physiology (PET scan images) and anatomy (CT Images), then fuses the two sets of images together to allow physicians to better understand the physiology of tissues seen on CT scan images.

PET (Positron Emission Tomography) scanning is a relatively new technology that has recently been seeing remarkable growth. More and more evidence is showing that PET/CT is the most accurate tool for imaging many cancers.

What to Eat and Drink The Night and Morning Before Your Pet/CT Scan

• FDG PET/CT Prep Instructions (PDF)
• FDG PET/CT Prep Instructions for Vegans and Vegetarians
• Prep Instructions for Cardiac Sarcoid Exam
• Dotatate PET/CT Prep Instructions

During The Exam

When you arrive, you will receive an injection of a diagnostic radioactive tracer. The tracer will take approximately one hour to travel through the bloodstream and distribute to tissues throughout the body. One hour after the injection, the scan will begin and last anywhere from 15 to 30 minutes.

How PET Imaging Works

Many cancers use more glucose (sugar) than most normal tissues. The Nuclear Medicine physician can take advantage of this by injecting glucose with a small amount of radioactivity attached to the glucose molecule. The PET scanner is then used to obtain images of the distribution of glucose metabolism throughout the body. The amount of glucose used by tissues in the body provides information to help guide further diagnostic and therapeutic options. In addition to using radioactive sugar (FDG) for PET imaging, other radiotracers are used in PET/CT at BIDMC for imaging neuroendocrine tumors, prostate cancer, as well as abnormal biomarkers in the brain.

What is the purpose of the CT scanner? The CT scanner is needed because the major disadvantage of PET imaging is that the anatomic detail seen in a PET scan is inferior to that of a conventional CT scan. This means that although PET can see the general location of an area of abnormal glucose uptake, the exact localization of the abnormality can be difficult using PET images alone.

Anatomic Information Obtained with CT Scanning

CT (Computed Tomography) scanning provides high-resolution images that show anatomy beautifully. But CT does not do a very good job of demonstrating physiology. Therefore, if an abnormality is seen on CT scanning, it is not always obvious if that abnormality is benign or malignant (cancer).

By obtaining both CT and PET images together, and fusing the images, the Nuclear Medicine physician can simultaneously see both anatomic and physiologic changes in the body that provide the most accurate information available today for the imaging diagnosis and localization of cancer.

Overview

This procedure provides a "roadmap" showing the direction of lymphatic drainage from around the site of cancer. Before this procedure was available, the surgeon would make her or his best estimate about the direction of lymph drainage from a tumor to the lymph nodes. The surgeon would then take out many lymph nodes in the area estimated to be the drainage pathway. Those lymph nodes would then be examined microscopically for signs of the spread of the tumor.

The sentinel node study, however, demonstrates more clearly and precisely the path of lymphatic drainage. This allows the surgeon to take out the specific node (or nodes) that are the first to receive lymphatic drainage from the area around the tumor. If these "sentinel" node(s) do not show any microscopic evidence of tumor, it is very unlikely that any other nodes would contain any tumor cells. Since fewer nodes are removed, the surgery is less extensive and recovery is faster.

The procedure involves no preparation on the part of the patient, other than the usual pre-operative instructions provided by the surgeon.

During The Exam

In Nuclear Medicine, the physician will inject a small amount of radioisotope in the region of the tumor. There are usually four to eight injections, depending on the type of tumor. The injections can feel like bee stings, but the pain usually subsides after a few seconds.

The exam may or may not involve imaging. In cases where the surgeon requests imaging, the technologist and the doctor will work together to image lymph nodes draining the region around the tumor. If lymph nodes are seen, the doctor may use a pen to put a mark on the skin overlying the lymph node to help the surgeon find the nodes.

In the operating room, the surgeon has a probe that detects the radioactivity in the lymph nodes. The probe is used either on its own, or in conjunction with the pictures to identify the sentinel node(s). Once the nodes are removed, they are sent to pathology for microscopic examination for evidence of the spread of the tumor.

Safety

As with most Nuclear Medicine studies, the radiation dose from this test is very small. In addition, the surgeon will likely remove much of the skin and the lymph nodes that contain the greatest amount of the injected radioactivity. The rest of the radioactivity will decay quickly. Following surgery, no special precautions are necessary.

What is a thyroid uptake and scan?

A thyroid uptake and scan is a test that provides information about how your thyroid looks and how well it works. The test is done in two parts on two separate days.

What happens during this test?

On the first day, you will be asked to swallow a small amount of radioactive iodine in capsule form. This visit should take about 15 minutes.

The next day, you will come back for the rest of the test—the scan and uptake procedures. This will take 60 minutes or longer.

The scan gives a picture of what the thyroid gland looks like. It shows the gland's size and shape, and whether there are any lumps or other abnormalities. For this part of the test, you will lie on a table with a camera above you. Four pictures of your thyroid will be taken. Then, a nuclear medicine doctor will examine your thyroid. We may then take more pictures to look at certain parts of your gland in more detail. This part of the procedure takes about 45 minutes.

The uptake procedure measures the amount of radioactive iodine your thyroid has absorbed. During this part of the test, a "counting device" will be placed a few inches in front of your neck. The amount of iodine in your gland will be counted by this device. This takes 10-15 minutes.

Is any special preparation required before this test?

If you are taking thyroid medicines or anything containing iodine, you may be asked to stop them for a time before this test. Check with your doctor about this.

Please don't eat or drink anything except water for four hours before your first appointment (the day the capsule is administered), as well as one hour after it. Please continue to take any medicine your doctor has prescribed.

PLEASE NOTE: If you are a diabetic, please check with your doctor several days before the test. Since you will not be eating normally, other adjustments may need to be made in your medications.

How do I get results?

A doctor from nuclear medicine will review the results and discuss them with your doctor. Your doctor will explain the results to you.

How safe is this test?

Nuclear medicine procedures are very safe. Your body can eliminate the radioactive materials that are used very quickly. The radiation dose from this test is between .17 and .26 rem. See Safety Information for a further discussion about safety.