Some cancer treatments can cause heart problems. This is a side effect called "cardiotoxicity." If you receive a cancer treatment that is known to cause heart problems, your health care team will want to monitor your heart. One scan they can use is a multigated acquisition scan or a MUGA scan. This may also be called an equilibrium radionuclide angiocardiography (ERNA) or radionuclide ventriculography (RNVG).
A MUGA scan creates a video of the blood pumping through the lower chambers, or ventricles, of the heart. This shows if there are problems with the way the heart is pumping and blood flow.
A MUGA scan is often done before a person starts cancer treatment. This helps your health care team understand your heart function before you receive treatment. It can also help them choose the best treatment for you. MUGA scans can also be done as a part of regular follow-up care after cancer treatment ends.
What causes heart damage during cancer treatment?
Certain cancer treatments can cause long-term damage to the heart. Your health care team may recommend that you get a MUGA scan or other scans to look at your heart if you have had:
Radiation therapy to the chest
Certain types of chemotherapy
Certain types of immunotherapy
Anthracyclines are a type of chemotherapy that are known to cause heart damage. Examples include danuorubicin (Cerubidine, Rubidomycin), doxorubicin (Adriamycin), and epirubicin (Ellence). Some immunotherapy treatments, like bevacizumab (Avastin),sorafenib (Nexavar), and trastuzumab (Herceptin), can also cause heart problems.
Sometimes, heart damage from these drugs can cause congestive heart failure (CHF). CHF happens when the heart does not pump enough blood to the rest of the body. People with CHF may experience swollen hands and feet, shortness of breath, dizziness, and an irregular heartbeat. Most often, however, the heart damage is mild and only seen on echocardiograms, MUGA scans, or other heart tests.
How does a MUGA scan work?
A MUGA scan uses a special camera to create computer-generated images of the beating heart. A small amount of a radioactive contrast medium or tracer, called technetium-99m-pertechnetate (Tc-99m), is injected into a vein. The tracer is like a dye. It binds to your red blood cells, which carry oxygen throughout your body. The camera picks up the radiation from the tracer as it travels through the heart.
Who does my MUGA scan? Where is a MUGA scan done?
A MUGA scan is done in the radiology department of a hospital or at an outpatient imaging center. It is done by a nuclear medicine technologist who has been trained and certified. A radiologist or a nuclear medicine physician oversees the technologist. Finally, a radiologist will interpret the scan results.
How should I get ready for a MUGA scan?
When you schedule the MUGA scan, you will get detailed instructions on how to prepare. Below, you will find general information about how to get ready for a MUGA scan. The specific instructions you receive may be different. Always follow the instructions of your health care team before a MUGA scan.
What to eat. You may not be able to eat or drink for 4 to 6 hours before the test. You may also be asked to avoid caffeine and tobacco products for up to 24 hours before the test.
What to wear. When you arrive for your MUGA scan, you may need to remove your clothing from the waist up. You will also need to remove any clothing, jewelry, or other metal objects that can interfere with the scan. Some people may need to do exercises during the MUGA scan, so wear comfortable clothing that you can move around in.
Your medications and health history. It is important that your health care team gets a full medical history from you before your MUGA scan. Be sure to talk to your health care team about the following:
Any medications you are currently taking. Heart medications like digoxin and nitrates can affect MUGA scan results. Your health care team will let you know if there are any medications you need to stop taking before your scan.
Any medical conditions you have, including a fast, irregular heartbeat or if laying flat or still is difficult for you.
If there is a chance that you are pregnant or if you are breastfeeding. If you are breastfeeding, you may need to stop breastfeeding for a set amount of time after the test. Your health care team will let you know how long you will need to stop breastfeeding.
Recent nuclear medical tests you've had, such as bone or thyroid scans.
Allergies. If you have any known medication allergies, including if you are allergic to barium.
Insurance, cost, and consent. If you are concerned about the cost of your MUGA scan, contact your insurance company beforehand. Ask how much of the cost you will have to pay.
When you arrive for your test, you will be asked to sign a consent form. This form says that you understand the benefits and risks of the scan and agree to have it. Be sure to ask the health care team about any questions or concerns you have.
What happens during a MUGA scan?
The MUGA scan may take up to 3 hours to complete, depending on how many pictures are needed. At the beginning of your appointment, the technologist will place stickers called electrodes on your chest. These measure your heart's electrical activity during the test.
The technologist will then inject the radioactive tracer into a vein in your arm. Sometimes, they will take a small amount of blood from your arm and mix it with the tracer. The technologist will then put the mixture back in your body through an intravenous (IV) line inserted directly into a vein. You will feel a small sting from the injection. But you will not be able to feel the tracer move through your body.
The technologist will ask you to lie still on a table and place a special camera above your chest. The camera is about 3 feet wide. It uses gamma rays to track the tracer. As the tracer moves through your bloodstream, the camera will take pictures to see how well the blood is pumping through your body. The pictures will be taken from many views.
You may be asked to exercise in between pictures. This helps the doctor see how your heart responds to the stress of exercise. The technologist may also ask you to take nitroglycerin to open your blood vessels and see how your heart responds to the medication.
What happens after a MUGA scan?
After the MUGA scan, you can return to your normal activities, including driving, right after the test. Your health care team may ask you to wait at the clinic or hospital while the images are being processed. If the images are blurry, you may have to do the scan again.
Drink plenty of fluids and urinate frequently for 1 to 2 days after the scan to help the tracer leave your body.
What do MUGA scan results mean?
The MUGA scan measures the amount of blood pumped out of your ventricles. A result of 50% to 75% is considered in the normal range. This means that your heart is efficiently pumping blood throughout your body.
Results below 50% or above 75% can mean that there is a problem with your heart, including heart damage from chemotherapy.
After your results are ready, a member of your health care team will discuss the results with you and let you know your next steps.
Questions to ask your health care team
Before having a MUGA scan, consider asking these questions:
Why are you recommending this procedure for me?
Who will perform my scan?
What will happen during the scan?
How long will the MUGA scan take?
What are the risks and benefits of having a MUGA scan?
Who can I talk to about the cost of this test?
When will I get the results? How?
Who will explain the results to me?
If the results are abnormal, what is the next step?
Will I need to have this test again during or after my cancer treatment?