Complete information on Thallium stress test

Find out how your heart works with the Thallium stress test
Thallium stress test is performed to determine how well the heart is supplied with blood. The Thallium stress test is a nuclear isotope scanning test and is used to determine the blood flow at rest and during activity. The activity that is generally conducted is the treadmill stress test.

Reasons for conducting a Thallium stress test

There are many reasons for conducting a thallium stress test and these include the following

The occurrence of chest pain that would require the doctors to find out if the blood supply to the heart is functioning well. This will guide the doctors on the right mode of treatment that should be given to the patient thereafter.
The test is also performed to understand the level of success of a heart procedure that was conducted earlier. This will help assess the surgery and will aid in deciding upon further treatment
The blocks in the vessels of the heart that would contribute to problems in the heart can be ascertained using this test.
The kind and the type of exercise that would be safe for a patient to carry out is another important factor that contributes to conducting this test. The doctor will be able to guide the patient on exercise schedules that he/she can carry out without stressing the heart.

The answers that are obtained on conducting the Thallium stress test will help the patient lead a more aware lifestyle, without causing undue stress to the heart.

Duration of the test

The Thallium stress test lasts for up to 4 hours and is normally interjected with a long break during which time one is allowed to eat a meal.

Preparation for the test

Do’s

Eat dinner early the previous night
Sip on water for medications
Do not eat anything after 12 midnight the previous night

Don’ts

Stay away from caffeine and any food that contains caffeine like colas and coffee. Even chocolates are ruled out on the day prior to the test.
Certain medications are also ruled out. These medications include medications for asthma.
If one is also diabetic and is on insulin, one should check with one’s doctor on how much insulin should be taken

The doctor should be asked for the medications that one would have to avoid prior to the test. Medications should be avoided for the described period of time only after consultation with the doctor.

The Thallium stress test

Step One:

The patient is required to perform an exercise after the doctor deems the patient fit enough to carry out the exercise. The exercise that is normally conducted is the treadmill test.

Step Two:

When the maximum level of exercise has been reached by the patient, the patient is injected with a small amount of thallium or sestambibi, which are radioactive material. This radioactive material will travel to the heart as one completes the exercise session.

Step Three:

The patient is then asked to lie down below a gamma camera which will aid in tracing the radioactive material in the heart.

Step Four:

The images that are captured by the gamma camera are transferred to a computer which will display the pictures.

Step Five:

Another set of images are taken after the patient rests for about 2-3 hours. This will give the images of the heart while the person is at rest.

Results

S.NO	Observation	Inference
1	The test is normal both during rest and during exercise	The patient gets sufficient supply of blood
2	The test is normal during rest but abnormal during exercise	The person gets normal blood supply to the heart while at rest but the heart is forced to work a lot harder during exercise. There may be a block in one or more of the coronary blood vessels
3	The test is abnormal both during rest well as during exercise	There may be blocks in the heart blood vessels
4	The Thallium is not witnessed in certain regions of the heart	The regions of the heart that do not show the presence of thallium may have been affected by a heart attack earlier.

This test is considered safe by a large number of people, with certain mild risks involved in the process. These include

Nausea , vomiting among certain people
Arrythmias or irregular heart beat
Difficulty in breathing
Skin rashes that may occur rarely

A variant of the Thallium stress test is conducted for those patients who are deemed unfit for the treadmill test by doctors. These are usually patient who suffer from conditions like arthritis or osteoporosis. The patient, in such cases, is injected with drugs that mimic actual exercise and pump up the heart rate. The drugs that are generally injected in such cases include adenosine or persantine. The thallium stress test that uses such drugs is named adenosine thallium stress test and persantine thallium stress test.

Adenosine thallium stress test and persantine stress test should not be conducted if the patient has any of the following conditions

If the patient is pregnant
If the patient is breast feeding
If the patient has a lung disease
If the person is allergic to adenosine or persantine

The Thallium stress tests are used routinely to determine the blood circulation in the heart. Any fears about the radiations form the radioactive material affecting one’s body is only for the technicians in the lab and does not extend to the patient who would take the test only occasionally.