Technetium-99m scanning of the Heart 

The test usually consists of two parts: after exercising and under resting conditions. There are many variations for performing the test, which depend on the department’s routine. The entire test may be completed in one day or on two separate days. You will be informed if the exercise or test portion will be done first.

As in a regular stress test, ECG electrodes will be attached to your chest. This will allow your physician to monitor your heart rate before, during, and after exercise. A blood pressure cuff will be placed on your arm to monitor your blood pressure before, during, and after exercise. Additionally, an intravenous (IV) line will be placed in a vein in your hand or arm to allow for ease of the Technetium-99m injection. The IV will be removed when the exam is completed.

The exercise part of the exam is usually done with a treadmill, very similar to a treadmill used at a health club. Exercising will begin slowly, and approximately every three minutes, the pace will increase. As you exercise, your heart rate and blood pressure will change. This is normal, and remember, you are being closely monitored throughout the exam. At your peak exercise, Technetium-99m  will be injected into the IV, and you will be asked to continue exercising for an additional one to two minutes.

Approximately 15 minutes after the exercise is complete, pictures will be taken of your heart using a special camera able to trace the Technetium-99m  that has localized in your heart. You will be asked to lie down on a special table. The camera will rotate above and around your chest while special pictures are being taken, which will take approximately 20 to 30 minutes to complete. You may breathe normally while the pictures are being taken. It is very important that you hold very still while the camera takes the pictures of your heart. You will not receive any radiation from the camera.

After about 30 minutes, a second injection of Technetium-99m will be given. The resting pictures are taken in the same manner as the exercise pictures. Remember, the order in which pictures are taken depends on the department’s imaging procedure. The total time needed for the test varies and may take from two to five hours.

What happens if I am unable to exercise?

Some people, because of a variety of disabilities, are unable to exercise adequately on a treadmill machine to achieve a diagnostic test result. In these cases, your doctor may decide to use a pharmacological stress agent to simulate the effect of exercise stress on your heart. These drugs are usually injectable medications. After they are injected and they begin to take effect, Technetium-99m is also injected into the bloodstream via the IV line. After about 15 to 30 minutes, you will be placed on a special table where a camera will take pictures of your heart. In some cases, your doctor may require you to perform exercise such as squeezing a rubber ball or other mild small movements while the pharmacological stress agent is being injected and before Technetium-99m is administered.

Are there any special preparations/instructions for the test?

Clothing: You should wear comfortable, loose-fitting clothing for exercise and comfortable shoes appropriate for walking.

Food: Your physician may instruct you to fast or to have a light breakfast and avoid certain foods such as milk products. It is important to avoid all caffeine intake for 24 hours prior to the test: do not drink coffee, tea, colas, or other soft drinks or eat chocolates, including candies, frosting, cookies, pies, cocoa, or chocolate milk for 24 hours prior to the test.

Medications: Be sure to tell your doctor all of the medications you are currently taking. Ask you doctor whether your medications should be taken before or held until after the test. Certain medications may interfere with the effectiveness of the exam.

Important Points to Remember

• There may be two parts to the exam. Return for the second part.
• You may receive an injection for each part of the exam.
• A written report of the test will be sent to your physician once it is interpreted.
• If you are pregnant or suspect you may be, notify your doctor before taking the test.

Pyrophosphate Technetium-99m Scanning

The pyrophosphate technetium-99m scan also uses technetium, but a different form than is used in the Sestamibi scan. The pyrophosphate scan is used to determine if a patient has had a heart attack and, if so, how much damage has occurred. Damaged heart muscle will take up this form of technetium within twelve hours after a heart attack. Normally, the ability for damaged heart muscle to take up pyrophosphate disappears within a week after a heart attack. This test can also be used to determine whether there is ongoing damage from the heart attack and whether the damage is confined to one area.