A nuclear stress test is a type of imaging test. It uses a camera and a radioactive tracer — a small amount of a radioactive substance injected into a vein — to reveal how a person’s blood flows during rest and activity.
Doctors use nuclear stress tests to check if a person’s heart muscles are getting enough blood flow. People also refer to these tests as thallium stress tests, myocardial perfusion scans, or radionuclide tests. Android Ecg Machine Factory
A person can take the test while resting or while exercising. During the test, a doctor injects a radioactive substance called a radionuclide, or tracer. This substance allows a person’s blood flow to become visible via a camera that picks up radioactive material.
A nuclear stress test generally takes 3–4 hours. Although the person experiences exposure to a small amount of radiation, medical experts generally consider the test safe.
Read on to learn more about nuclear imaging tests, such as their benefits, how they work, and their risks.
The nuclear stress test can help doctors diagnose certain heart conditions. They do this by providing important information about a person’s heart, such as:
Additional benefits of a nuclear stress test include:
During a nuclear stress test with exercise, a doctor injects a tracer into a vein in a person’s arm. Once the tracer is absorbed, a gamma camera takes pictures of the heart. Medical professionals perform this test while the person is lying down.
The person then moves onto a treadmill or stationary bicycle. When a person’s heart is working at its hardest, doctors inject them with another dose of tracer. Once absorbed, the person can resume exercising. During this time, the gamma camera takes photos of the person’s heart.
People with mobility issues, or conditions such as arthritis, may be unable to do physical exercise. These people may do a chemical or pharmacologic stress test.
In a chemical stress test, medical professionals inject a person with medication such as:
This medication increases a person’s heart rate, mimicking the effects of exercise.
On the day of the test, a person should wear comfortable, loose-fitting clothes. They should also wear shoes that are comfortable to exercise in.
The American Heart Association (AHA) notes that a person should not eat anything for 4–6 hours before the test. A person can still drink water during this time.
A doctor may ask a person not to eat or drink anything containing caffeine 24 hours before the test. A person should not smoke or use tobacco products for at least 8 hours before the test.
A person should inform their doctor about any medication or supplements they take. Certain medications may interfere with the test.
Medications that may affect a nuclear stress test include:
Before a nuclear stress test, a person should inform their doctor if they are pregnant or may be pregnant. Radiation from the tests may be harmful to a developing fetus.
Nuclear stress tests take place in the hospital or specialized clinic. A nuclear stress test contains the following steps:
Some clinics may monitor a person during exercise first and then rest. Certain clinics may do one test one day and the other the next day.
Following a nuclear stress test, a healthcare professional will monitor a person for 10–15 minutes or until their heart rate returns to pre-exercise levels.
The tracer will pass through a person’s body and into their urine. A person can drink plenty of water to help remove it faster.
A person should avoid babies or young children for the rest of the day following a nuclear stress test. A person may have residual radiation due to the test.
A person can make arrangements to discuss the results of the test with their doctor.
Information from 2022 suggests that the most common side effects of a nuclear stress test are a headache and feeling flushed. Other possible side effects include:
In rare cases, a person may be allergic to the tracer used during the test.
Two drugs used for nuclear stress tests — Lexiscan and Adenoscan — carry a rare risk of heart attack and sudden death. Health professionals use these drugs to simulate exercise in people who are unable to do so.
The drugs work by increasing blood flow to help identify blockages. This could cause blood to flow more effectively to unobstructed areas, leaving problem areas without blood. In rare cases, this could lead to a heart attack.
Healthcare professionals should not use these drugs in people with unstable angina or other cardiac instability.
Research from 2018 suggests radiation exposure from a nuclear stress test is low. However, the AHA notes that there is a possibility that even low levels of radiation may be harmful.
A person should not have a nuclear stress test if they have low heart attack risk and no symptoms of heart issues.
Once a doctor receives the results of the nuclear stress test, they can discuss them with a person.
If a person has typical blood flow during both rest and exercise portions of the test, it suggests that their heart is functioning as expected.
However, results can show reduced blood flow to a person’s heart. This can be a result of conditions such as:
A doctor may therefore recommend further testing.
A nuclear stress test uses a small amount of a radioactive substance to examine a person’s blood flow during rest and activity.
It involves a radioactive substance called a radionuclide, or tracer. This makes a person’s blood flow visible via a camera, which can detect certain heart conditions. While the test is generally considered safe, it is not suitable for pregnant people or individuals with low heart attack risk.
People can discuss the test results with a doctor, who will arrange further tests or treatments if necessary.
Last medically reviewed on November 30, 2022
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