Nuclear medicine is a branch of medical imaging that uses radioactive materials for diagnosis and therapy. It is an invaluable tool in providing your physician with the needed diagnosis so appropriate treatment can be planned.
In diagnosis, radioactive substance, known as radiopharmaceuticals, are administered to the patient and the radiation that is emitted is detected by a gamma camera. Different radioactive materials are used that attach themselves to different organs or systems in the body.
A typical nuclear medicine study involves the administration of the radio-pharmaceutical in liquid or aggregate form, ingestion while combined with food or inhalation of the product in the form of a gas or aerosol.
The end result of a nuclear medicine imaging process is a “dataset” comprising of one or more images. The images are reconstructed by a computer to for detailed pictures for interpretation by a physician who has been trained in nuclear medicine.
Prior to Procedure
For 24 to 48 hours before the test, do not eat or drink any foods or take any of the medications listed below:
- Beverages containing caffeine (such as coffee, tea, colas, or other soft drinks)
- Foods containing caffeine, such as chocolate (including candies, frosting, pies, cakes, cookies, cocoa, or chocolate milk)
- Over-the-counter pain relievers that contain caffeine, including Anacin and Excedrin
- Products that contain theophylline such as Constant-T, Primatene, Quibron, Slo-Phyllin, or Theo-Dur
- Dipyridamole (Persantine)
Read product labels and ask your doctor or pharmacist for more information about what products you should avoid before the test.
You may be asked to avoid eating or drinking for 4 to 8 hours before the test. Wear loose clothing and low-heeled shoes with rubber soles or tennis shoes. If you smoke, ideally you should avoid smoking for one to two days before the test, or at a minimum for at least four hours before the test. If you have diabetes, and take medication or insulin for this condition, make sure to ask your doctor how to adjust your medication and food intake for this test.
Tell your doctor, or whomever is conducting the test, if you:
- Have a history of allergies
- Are taking any medications or herbal supplements
- Have diabetes
- Are pregnant or might be pregnant
- Are breastfeeding
- Have any prosthetic implants in your body
The test usually consists of two parts. One part of the test looks at the normal functioning of the heart at rest. The other part of the test, called “stress,” examines the heart after exercise, or after taking a drug that mimics the effect of exercise on the heart. The doctor interpreting the test will compare the exercise and resting images to evaluate the health of your heart. The order of the parts of the test will vary based on the protocol. You will be informed if the exercise or the rest portion will be done first.
Anesthesia is not needed.
Description of the Procedure
A blood pressure cuff is placed on one arm. An intravenous line (IV) is inserted in your other arm. Small round pads (ECG electrodes) are placed on your chest and attached to an electrocardiograph. This allows the doctor to monitor your heart rhythm. Your blood pressure and heart rate are monitored before, during, and after you have exercised.
The doctor or nurse will inject a small amount of radioactive material, like thallium, via the IV into your bloodstream. The amount of radioactivity in these materials is very small. The radioactive tracers concentrate in the parts of the heart that have the best blood flow, and emit signals that can be detected by a special camera. Images taken by the camera show any parts of the heart that are not getting enough blood. These images are taken while you are at rest and while you exercise.
The exercise or “stress” part of the test is usually done with a treadmill. You begin by slowly walking on the treadmill, and the pace increases gradually every three minutes. As you exercise, your heart rate and blood pressure will change. At your peak exercise, the tracer is injected into the IV and you will continue exercising for another one or two minutes.
Approximately 15 to 30 minutes after exercising, you will lie down on a special table as images are taken of your heart.
If you are unable to exercise for any reason, the doctor may use a drug that mimics the effect of exercise on the heart. If you notice any changes in the way you feel, or experience any side effects, notify the clinician who is monitoring the test.
You can get dressed and go home. Follow your doctor’s recommendations.
How Long Will It Take?
The entire test takes a minimum of 3 hours. You may receive the entire test in one day, or you may have each part of the test on two separate days.
Will It Hurt?
In general, this test should not be painful. If you were given a dilating medication, you may feel some discomfort such as flushing, chest pressure/pain, or shortness of breath.
If you receive a medication that increases the work of your heart, you may experience symptoms of anxiety, dizziness, nausea, shakiness, or shortness of breath. Let the clinician monitoring you know if you have any of these symptoms. There is a possibility that you may experience some effects from dilating medication for up to 24 hours after the test.
If you have coronary artery disease, you may feel chest pain or angina during the stress portion of the test. A specialist will be nearby and may give you medication for the symptoms or stop the test early. Let the clinician know if you have any symptoms of jaw, neck, arm, or chest discomfort.
You will be exposed to a small dose of a radioactive substance. Your doctor will use the smallest amount of radioactivity possible to get test results. Cardiac nuclear imaging has been performed for more than 30 years and no serious long-term effects have been reported. Of course, if you are pregnant, exposure to radiation should be avoided unless absolutely necessary. If you think you may be pregnant, let your doctor know.
Average Hospital Stay
The test may be conducted on an inpatient or outpatient basis. Patients are not typically admitted for this procedure.
There is no special care necessary after this test.
The doctor will compare the images taken of your heart during rest with the images of your heart during stress. If your heart is relatively healthy, there should be little or no difference between the images taken during stress and those taken at rest. If your heart has partially blocked arteries, images taken during stress will be different from those taken at rest.
Call Your Doctor If Any of the Following Occurs
- Your symptoms continue or worsen
- You develop any new symptoms
- You continue to experience side effects from dilating medication
Where and When?
Nuclear medicine studies are performed in our radiology department. Emergency studies are performed on an as needed basis 24 hours a day, 7 days a week. Typically, outpatient studies are scheduled Monday through Friday, and an appointment can be made by calling (855) 226-9105 (toll free).