In nuclear heart scans, the tracer is injected into your blood and travels to your heart. Nuclear heart scans use single-photon emission computed tomography (SPECT) or cardiac positron emission tomography (PET) to detect the energy from the tracer to take pictures of your heart. This imaging test can detect if blood is not flowing to parts of the heart and can diagnose coronary heart disease. This procedure can also check for damaged or dead heart muscle tissue, possibly from a previous heart attack, and assess how well your heart pumps blood to your body. Compared to SPECT, PET takes clearer pictures; however, both options may be used.
A nuclear heart scan may be performed in a medical imaging facility or hospital. Your heart will be monitored during this test with an electrocardiogram (EKG). Two sets of pictures will be taken, each taking 15 to 30 minutes. The first set of pictures is taken right after a medicine stress test or an exercise because some problems can be detected only when the heart is working hard or beating fast. If you are unable to exercise, your doctor may give you medicine to increase your heart rate. Shortly after the stress test, the tracer will be injected into a vein in your arm. There may be bruises at the injection site. You will lie still on a table that slides through a tunnel-like machine as the first set of pictures is taken. The second set of pictures will be taken the same day or the next day after your heart rate returns to normal.
Nuclear heart scans carry few risks. The amount of radiation in this test is small. In rare cases, some people experience treatable allergic reactions to the tracer. If you have coronary heart disease, you may experience chest pain during the stress test. Medication can help relieve your chest pain. Talk to your doctor and the technicians who perform the tests about whether you are or may be pregnant. If the test is not urgent, you may have to wait to do the tests until after your pregnancy. Let your doctor know if you are breastfeeding as radiation can pass into your breast milk. If the test is urgent, you may need to pump and store enough breast milk for one to two days after the test, or you may bottle-feed your baby for that time.
What is Nuclear Heart Scan?
Nuclear heart scans are performed to provide vital information regarding your heart condition.
In this test, a safe radioactive substance called a tracer is injected into your bloodstream through a vein. The tracer then travels to your heart and releases energy which is detected by a special camera and a computer to create images of the inside of your body.
Nuclear heart scans are used for three main purposes:
- To evaluate how your blood flows to the heart muscle. If parts of the heart muscle are not getting blood, it may be a sign of coronary heart disease (CHD). CHD may lead to chest pain called angina, heart attack, and other heart problems. When a nuclear heart scan is performed for this purpose, it is called a myocardial perfusion scan.
- To determine a damaged heart muscle. It may be caused by a previous heart attack, injury, infection, or drugs. When a nuclear heart scan is performed for this purpose, it is called myocardial viability testing.
- To evaluate how well your heart pumps blood to your body. When a nuclear heart scan is performed for this purpose, it is called a ventricular function scan.
Usually, two sets of pictures are taken during a nuclear heart scan procedure. The first set is taken right after the stress test, while your heart is beating fast.
During a stress test, you will exercise to make your heart work hard and beat fast. If you are unable to exercise, you may be given medication to increase your heart rate. This is called a pharmacological stress test.
The second set of pictures is taken later, where your heart is resting and beating at a normal rate.
What is Shown in Nuclear Heart Scans?
The nuclear heart scan results may help doctors in:
- Diagnosing heart conditions, such as coronary heart disease (CHD), and determining the best treatment.
- Controlling certain heart diseases, such as CHD and heart failure, and predicting short or long-term survival.
- Determining your risk for heart attack.
- Determining if other heart tests or procedures may help you. The tests and procedures may include coronary angiography and cardiac catheterization.
- Determining if a medical procedure that increases blood flow to the coronary arteries will help you. The procedures may include percutaneous coronary intervention, also known as coronary angioplasty, and coronary artery bypass grafting (CABG).
- Monitoring recent medical procedures or surgeries, such as CABG or heart transplant.
What are The Risks of Nuclear Heart Scans?
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During the procedure, you will be exposed to small amounts of radioactive materials (radioactive tracers). There have been no long-term effects reported from the small amounts of radiation.
The dose used may be a concern for people who need multiple scans. However, the advancement in technology can significantly reduce the radiation exposure.
In rare instances, some people may have allergic reactions to the radioactive tracers
If you have coronary heart disease, you may experience chest pain during a stress test while you are exercising or taking medicine to increase your heart rate. Medication may relieve these symptoms.
If you are pregnant, be sure you tell your doctor or the technicians performing the scene. They may have to postpone the scan until after you give birth.
What to Expect Before Nuclear Heart Scans?
Nuclear heart scans may take a lot of time. Most scans usually take between 2-5 hours, especially if your doctor needs two sets of pictures.
Discuss with your doctor how the procedure is performed. Talk to your doctor about your overall health condition, including health problems such as asthma, COPD (chronic obstructive pulmonary disease), diabetes, and kidney disease.
If you have lung disease or diabetes, your doctor may give you specific instructions before the procedure.
If you are having a stress test as part of a nuclear heart scan, be sure to wear comfortable shoes and loose clothing for the test. You may be asked to wear a hospital gown during the test.
Furthermore, you should also let your doctor know about any medications you are taking, including prescription and over-the-counter medicines, vitamins, minerals, and other supplements. Some medicines and supplements may interfere with medications used during a stress test to increase your heart rate.
What to Expect During Nuclear Heart Scans?
What to Expect During Nuclear Heart Scans
You can find nuclear medicine centers in many hospitals. A specialist doctor with special training in nuclear heart scans — a cardiologist or radiologist — will supervise the test. Cardiologists are doctors who specialize in diagnosing and treating heart problems. A radiologist is a specialist doctor who has special training in medical imaging techniques.
Before the test begins, your doctor or the technician may insert a needle into your vein for the intravenous line. Through this IV line, your doctor will insert the radioactive tracers into your bloodstream. You will also have an EKG (electrocardiogram) patch on your body to check your heart rate during the test. (An EKG is a simple test that detects and records the heart’s electrical activity.)
During Stress Test
If you have to perform an exercise stress test as part of your nuclear scan, you may be asked to exercise on a treadmill or stationary bicycle. Usually, a stress test includes an electrocardiogram to measure your heart’s electrical activity. Your doctor may also measure your blood oxygen level, blood pressure, and heart rate.
Your doctor will stop the test if you are too tired to continue the test, have shortness of breath, or experience chest or leg pain. You may expect a faster heartbeat, a faster breath, increased blood pressure, and sweating. Tell your doctor if you experience chest, arm, or jaw pain or any discomfort. You should also let your doctor know if you feel dizzy or other unusual symptoms.
If you are unable to exercise, your doctor may give you medicines to increase your heart rate. This is called a pharmacological stress test. The medicine given may make you feel anxious, nauseous, dizzy, or shaking for a short period of time. If the side effects are severe, your doctor may give you other medications to relieve symptoms.
Before the exercise or pharmacological stress test ends, the radiotracers is injected through an IV line.
During Nuclear Heart Scans
The nuclear heart scan will begin immediately after the stress test. You will lie still on a padded table. The nuclear heart scan camera, called a gamma camera, is enclosed in a metal housing. The camera can be placed in several positions around your body as you lie on the padded table.
For some nuclear heart scans, the metal housing is shaped like a donut (with a hole in the center). You lie on a table that slowly moves through the hole. A computer nearby or in another room collects pictures of your heart. Usually, two sets of pictures are taken. One will be taken right after the stress test and the other will be taken after a period of rest. The pictures may be taken all in 1 day or more than 2 days. Each set of pictures takes about 15-30 minutes.
Some people find it hard to stay in one position during the test. Other people may feel anxious when lying on the donut-shaped scanner. The table may feel hard, and the room may feel cold because of the air conditioning needed to maintain the machines. Let your doctor or technician know how you are feeling during the test so that they can respond as needed.
What to Expect After Nuclear Scans?
Your doctor may ask you to return to the nuclear medicine center on the second day for more pictures. Outpatients will be allowed to go home after the scan or leave the nuclear medicine center between two scans.
Most people can return to their daily routine after a nuclear heart scan. The radioactivity will naturally leave your body through your urine or stool. It is helpful to drink plenty of fluids after the test, as your doctor recommends.
The cardiologist or radiologist will read and interpret your test results. He or she will report the results to your doctor, who will contact you to discuss them. Alternatively, a cardiologist or radiologist may contact you directly to discuss the results.