The tracer will lose its radioactivity through natural decay in about a day or two.
This article discusses the purpose, types, and potential risks of a nuclear stress test.
It will also help you prepare by knowing what to expect before, during, and after the procedure.
Verywell / Emily Roberts
A nuclear stress test is different than a regular stress test.
The nuclear stress test uses a radioactive tracer to make a picture.
The tracer that is commonly used today is calledtechnetium-99 (Tc-99).
It provides clearer images than the tracers used in the past.
It also exposes a patient to less radiation.
What the Test Is Looking For
The nuclear stress test creates two images.
The first shows how blood flows to your heart when you are resting.
The second shows the blood flow during exercise.
It will also help your provider decide what kinds of daily activities and exercise you should be doing.
The nuclear stress test does not involve inserting medical instruments into your body.
This means it is non-invasive.
The test is thought to be the most accurate and non-invasive way to diagnose coronary artery blockages.
If you’re able to have a nuclear stress test, you may not need to have cardiaccatheterization.
Risks and Contraindications
When performed by experienced providers, the nuclear stress test is very safe.
Still, there are known risks.
Radiation Exposure
During a typical nuclear stress test, you are exposed to 11millisievertsof radiation.
A dose of 11 millisieverts is considered a small amount of radiation exposure.
By itself, it should not increase your lifetime risk of cancer by any measurable amount.
The risk of radiation exposure to other people after a nuclear stress test is low.
Out of an abundance of caution, you may also want to avoid close contact with pets.
They are estimated to occur only in one out of every 10,000 exercise tests.
Who Should Not Get the Test?
Some people should not do nuclear stress testing.
The types of drugs used may include:
Vasodilators are usually preferred for the pharmacologic stress test.
These are medications that dilate or bring up the blood vessels.
Your provider will choose the best drug for your case if exercise is not an option.
Before the Test
It is normal to have some anxiety about having a nuclear stress test.
Knowing how to prepare and what to expect may help relieve your nerves.
Timing and Location
Most nuclear stress tests are performed in a hospitaloutpatientdepartment.
You will probably be asked to show up at least 30 minutes before the scheduled test.
you could expect to be at the hospital for at least four hours.
Many people bring gym clothes and walking or running shoes.
Most testing facilities will provide a place for you to change your clothes.
You will also be asked not to smoke for four to six hours before you arrive.
You will also need to avoidcaffeinefor at least 24 hours before the test.
You may also need to stop aspirin,blood thinners, and asthma medications 48 hours before the test.
If you have health insurance, the cost will also depend on your coverage.
Mostmedical insurancewill cover a nuclear stress test if a qualified cardiologist says that you need it.
To be sure, check with your insurance company before you have the test.
What to Bring
You will probably have a few hours of downtime during the test.
This person can keep you company and offer support if you expect to get the results.
Pre-Test
After you arrive for testing, you will be interviewed by someone on your healthcare team.
This person will ask if your symptoms or medical condition have changed since you last saw your provider.
You will also have a quick physical exam.
Your team will let you know what to expect during the test.
You will also be given a chance to ask questions.
The testing will be overseen by a healthcare provider.
They will tell you who they are and what they do prior to beginning the test.
Most labs do one-day nuclear stress testing but it can also be done over two days.
One-day testing is generally more convenient for patients.
If you are doing a one-day test, a resting image is captured first.
The exercise part will be done later the same day.
For a two-day test, the exercise part is usually done on the first day.
The resting part is done on the second day.
This image only needs a small dose of Tc-99.
It is captured with a special camera that is used to scan the chest (gamma camera).
After about 20 minutes, you will lie down under the gamma camera.
You will need to keep your arms above your head and lie still.
It will take another 15 to 20 minutes to make the image.
The image will show how the blood is flowing to your heart.
Before the exercise test, electrodes will be placed on your chest.
The electrodes allow anelectrocardiogram(ECG) to be recorded while you are exercising.
This test measures the electrical rhythm of your heart.
The level of exercise will increase every three minutes.
The exercise itself usually lasts for no more than six to 12 minutes.
When you have reached the maximum level of exercise, the tracer will be injected into your IV.
At that point, you will stop exercising.
For the exercise image, the Tc-99 dose is much larger than it was for the resting image.
Twenty to 30 minutes after you’ve finished exercising, you will lie under the gamma camera again.
You will be asked to keep your arms above your head.
The exercise cardiac image takes about 20 minutes to make.
After the Test
Most people can go back to their normal routine immediately after the test.
This includes having meals, taking medications, and doing other activities.
How and when you get your results depends on the testing center.
Most laboratories will give you an overview of the results right away.
If the test finds problems, you’ll be given advice on what to do next.
In this case, you’ll get your results from the provider who ordered the test.
From there, you’ll discuss what, if anything, should be done next.
Managing Side Effects
Most people don’t experience any significant side effects from a nuclear stress test.
When they do occur, side effects may include:
More serious side effects are uncommon.
If you have any unusual symptoms after the test, call your provider.
Interpreting the Results of a Nuclear Stress Test
The interpretation of the results is different for everyone.
You’ll need to discuss the results with your provider.
In general, the results of a nuclear stress test fall into three categories.
In this case, the chance of having CAD is low.
Your healthcare provider will discuss the next steps with you.
If your test is normal, you may not need more cardiac testing.
The goal will be to relieve symptoms and slow the progression of the disease.
You may also need to have a different test.
For example, your provider may want you to have cardiac catheterization if:
2.
For example, a person could have a permanent defect in one part of the heart muscle.
This indicates a heart attack has occurred.
They may also have a reversible defect in another part of the heart muscle.
This indicates there is a blockage but no permanent damage.
Summary
A nuclear stress test is used to find heart problems.
The test uses a small amount of radioactive material to record blood flow to your heart.
The test is done while you are at rest and exercising.
The nuclear stress test is generally very safe.
The amount of radiation used is very small and does not increase your lifetime risk of cancer.
Your provider will discuss the next steps with you, depending on the results.
2014;20(2):65-90. doi:10.1016/j.cardfail.2013.12.002
National Library of Medicine.Nuclear stress test.
2021;36(2):163-167. doi:10.4103/ijnm.ijnm_219_20
American Heart Association.Cardiac catheterization.
