What is a Thallium Scan?

14 May 2010
Posted by shalini

Thallium or cardiolite scanning is a diagnostic technique that uses a radioactive isotope or a tracer to evaluate the amount of blood reaching different parts of heart. These are included in the category of nuclear medicine scans. It is otherwise known as thallium imaging or myocardial perfusion scan or cold spot imaging. This method is used to distinguish the location and size of the damaged muscles, especially after undergoing a heart attack. This scan will enable your doctor to have a more detailed view of your heart and the structures supporting it. Thallium scan will help a cardiac specialist to evaluate the blood supply and the reparative function of heart even after a bypass surgery or coronary by-pass grafting. It is a common diagnostic measure nowadays to illustrate the status of coronary blood vessels and the heart chambers.

thallium scan


You need to lie on a bed; meanwhile a tiny amount of thallium or the cardiolite is injected into a vein in the arm. This tracer is taken up by the strong healthy muscles of your heart and if not absorbed, it appears as dark spots called cold spots on the scan image and hence the name called as cold spot imaging. The images are formed by a gamma camera which grabs the amount of radiations given out by the tracers infused into the blood stream. Thallium scans are also done after a few hours of exercise, as it will increase the pumping of heart which improves the blood supply and hence the absorption of thallium or the cardiolite.  

The radiations are usually non ionizing type hence not very hazardous, and the amount absorbed by the body is almost the same as that you gain from a chest x-ray. Therefore the risk of the procedure is relatively high.

You have to keep nil per oral, means should keep away from any food or drink at least for three hours before the test, and should abstain from any of the beverages, tobacco, alcoholic drinks ,over the counter medications etc, about 24 hours prior to the procedure. You have to tell the doctor regarding any allergies or any morbidity apart from this before the procedure.

Usually the cardiolite or the thallium scans are conducted in conjunction with any stress tests so as to promote the early identification and treatment of coronary artery disease.

As discussed earlier, thallium will be taken in enormous quantities by the coronary arteries and veins that supply blood to the heart, and in case of any blockage the cardiolite will get accumulated at the specific area resulting in the formation of the cold spots.

cardiolite scan


Thallium or the cardiolite scans has increased the accuracy of the cardiac stress tests. Thallium tests are very effective in the diagnosis of obstructive coronary disease. A normal test of thallium or cardiolite test is a good indication of a healthy heart and coronary blood vessels, and you need not have to worry any more about your heart. Whereas a significantly abnormal thallium scan report shows that you need an immediate treatment for the blockages or the ill function of your heart. Thallium scan is safe and the only disadvantage is with the radiation; but since the radiations are of short range, they are not much hazardous. And also the benefit from thallium scans outweighs a lot more than the small risk that it exerts over the patient.

Cardiolite or the thallium scans could thus diagnose the disease in an easier and a painless manner. Since it is least invasive, there is no severe complications of infection or any other scars. The consent has to be taken from either the patient or the family saying that they agree to the procedure. The health professionals have to explain to the patient the whole procedure, its benefits. etc so that the patient may have a slight relief from anxiety. After the procedure patient should be kept under observation for any chills or hypotension. Check the vital signs and provide a quiet environment for the patient to rest for some time. Patient should take plenty of water and remain in the bed for a few hours. Also patient is allowed to take food and regain all his activities within a few hours.




Thallium scan - medical advivce

My cousin aged 40 is having cholesterol 700 and doctors have suggested thallium scan. Is this is the required procedure? Also please advice me is it a safe procedure for him. 

Re: Thallium scan - medical advice

Does he have any chest pain?

Did he already have a  treadmill test?, sometimes before having thallium scan ( consider radiation) a stress echo cardiogram might be better option.  
However is it total cholesterol? what is his LDL cholesterol, is he on any medication?
If your  cousin is under medication and LDL choesterol is exorbitantly high, there is probably a genetic defect in the LDL receptor.
Sometimes you have to consider LDL apheresis. 


Medical Team 

Heart Consult

Very good information ,thanks

Very good information ,thanks

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