To diagnose coronary artery disease, physicians must be able to “see” the coronary arteries and the shape and function of the heart chambers. One easy way to do this without inserting catheters or other instruments into the body is the thallium exercise scan, which is done on an outpatient basis.
Thallium is a radionuclide that shows up on a special scanning device. Thallium is injected into the arm during a treadmill test. A series of pictures is made of the location of the isotope in the heart. Dark areas of the scan indicate portions of the heart where blood flow is impaired.
Thallium exercise scanning cannot provide a picture of the actual blocked artery, but can show the part of the heart affected and may substitute for the more invasive angiogram, which requires a hospital stay. The actual amount of radioactive material injected is slight.
A thallium exercise scan is often recommended when the ECG exercise test is abnormal. If you have been recommended for a thallium exercise scan, it means that your heart may not be functioning correctly and you could be in danger of a heart attack. Ask your healthcare provider to explain the risks of your condition and the results of your test. Discuss the steps you can take to improve the health of your heart.