What is a Thallium Stress Test?
A "thallium stress test" (sometimes mistakenly referred to as a "thalium stress test") is a special type of "nuclear stress test" performed to measure how well blood flows to your heart. A thallium stress test is usually performed along with an exercise stress test on a treadmill or bicycle.
A thallium stress test can help to determine:
- Extent of a coronary artery blockage
- Prognosis for patients who've suffered a heart attack
- The effectiveness of cardiac procedures done to improve circulation in coronary arteries
- One or more cause(s) of chest pain
- The level of exercise that a patient can safely perform
When the patient reaches his or her maximum level of exercise, a small amount of a radioactive substance called "thallium" is injected into the patient's bloodstream. After exercise, the patient lays down on a table and a camera takes one or more pictures of the chest area around the patient's heart. The camera is a special type of camera that can see the thallium in the patient's blood stream, and takes pictures of the dispersal of the thallium in the patient. The thallium mixes with the blood in the bloodstream and heart's arteries and enters heart muscle cells. Normal heart tissue, that is receiving a normal amount of blood flow, will show even dispersal of the thallium. Areas of the heart tissue that are not receiving normal flow of blood will appear in the pictures as areas where no (or little) thallium has spread.
The first pictures are made shortly after the exercise test and show blood flow to the heart during exercise. The heart is "stressed" during the exercise test — thus the name "stress test." The patient then lies quietly for 2-3 hours and another series of pictures is made. These show blood flow to the heart muscle during rest. These pictures are compared and studied by the doctor to identify any heart-related issues.