Thallium stress test is a nuclear imaging method that shows how well blood flows into the heart muscle, both at rest and during activity.
This test is done at a medical center. The test is done in two parts:
Part 1: You will walk on a treadmill (or pedal on an exercise machine).
Part 2: The health care provider will inject a radioactive substance into one of your veins and then take pictures of your heart.
The first pictures are taken shortly after you get off the treadmill or are given the vasodilator drug. These images show how blood flows to the heart during exercise. This is the part most commonly referred to as the "stress test," because it is the most challenging for your heart.
After lying quietly for a few hours, you'll have more pictures taken of the heart. These images show blood flow through your heart at rest.
The entire test can take about 4 hours. You will usually be given a long break in between scans and allowed to have a caffeine-free lunch or a snack at a nearby cafeteria.
You should wear comfortable clothes and shoes with nonskid soles. You will probably be asked not to eat or drink anything after midnight, except for a few sips of water if you need to take medicines.
You will need to avoid caffeine for 24 hours before the test. This includes caffeinated beverages such as tea, coffee, and sodas, as well as chocolates, and certain pain relievers.
Your doctor will tell you if you need to stop taking any medicines before the test. Medications used to treat asthma and angina may interfere with test results. Never stop taking any medicine without first talking to your doctor.
It is important to tell your doctor if you have taken a dose of the following medications within the last 24 hours:
Some people feel fatigue, muscle cramps in the legs or feet, shortness of breath, or chest pain during the treadmill test.
If you are given the vasodilator drug, you may feel a sting as the medication is injected, followed by a feeling of warmth. Some patients also have a headache, nausea, and a feeling that their heart is racing.
Rarely, during the test people experience:
If any of the symptoms listed above appear during your test, let the lab personnel know immediately.
The test is done to see whether your heart muscle is getting enough blood flow, and therefore enough oxygen, when it is working hard (under stress).
Your doctor may order this test to determine:
The results of a nuclear stress test can help your doctor:
A normal result means blood flow through the coronary arteries is normal.
Note: Normal value ranges may vary slightly among different medical centers. Talk to your doctor about the meaning of your specific test results.
Abnormal results may be due to:
After the test you may need:
Complications are rare but may include:
Your health care provider will explain the risks before the test.
Breast tissue in women and nonheart tissues such as the diaphragm can sometimes cause false positive test results. Further tests may need to be done to confirm the results. These may include a stress echocardiogram or a cardiac catheterization.
Sestamibi stress test; MIBI stress test; Myocardial perfusion scintigraphy; Dobutamine stress test; Thallium stress test; Stress test - nuclear