Nuclear Stress Test
Thallium stress test is a nuclear imaging method that shows how well blood flows into the heart muscle, both at rest and during activity.
You will walk on a treadmill (or pedal on an exercise machine).
Gradually you will be asked to walk (or pedal) faster and on an incline.
If you are not able to exercise, your doctor will give you a medicine called dobutamine. This medicine will make your heart beat faster and harder, similar to when you exercise.
Your blood pressure and heart rhythm will be watched (monitored) the whole time.
The health care provider will inject a radioactive substance into one of your veins and then take pictures of your heart.
The radioactive material may be thallium or sestamibi. (If sestamibi is used, it's called a "sestamibi stress test.") This substance travels through your bloodstream into the heart muscle.
Next, you will be asked to lie down on a table under a special camera that scans the heart. A computer creates pictures of the heart by tracking how the radioactive material moves through the area.
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.
How to prepare for the test
The entire test can take about 4 hours.
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.