What is Cardiac Nuclear Imaging?
Cardiac nuclear medicine is useful in diagnosing and assessing coronary artery disease. It is also used to evaluate cardiomyopathy and identify possible damage to the heart from chemotherapy or radiotherapy.
Nuclear medicine imaging procedures are noninvasive. With the exception of intravenous injections, they are usually painless. These tests use radioactive materials called radiopharmaceuticals or radiotracers to help doctors diagnose and evaluate medical conditions.
Cardiac nuclear medicine exams provide pictures of the distribution of blood flow to the heart muscle and can be used to visualize the function of the heart.
How should I prepare?
You may wear a gown during the exam or be allowed to wear your own clothing.
Women should always tell their doctor and technologist if there is any possibility that they are pregnant or they are breastfeeding.
Tell the doctor and the technologist performing your exam about any medications you are taking, including vitamins and herbal supplements. List any allergies, recent illnesses, and other medical conditions.
You should inform your physician if you are pregnant or breastfeeding and/or if you have:
had a recent heart attack or myocardial infarction
chronic lung disease
conduction abnormalities within the heart (such as AV block), aortic stenosis or other abnormalities with the valves of your heart
any abnormality with the heart and lungs
Also, if you have problems with your knees, hips or keeping your balance, tell your doctor as this may limit your ability to perform the exercise needed for this procedure. You should wear comfortable clothing and walking shoes. Do not apply oil, lotion, or cream to your skin on the day of the exam. If you use an inhaler for asthma or other breathing problems, bring it to the test and make sure the health care team monitoring your stress test knows that you use an inhaler.
Leave jewelry and other metallic accessories at home or remove them prior to the exam. Such objects may interfere with the procedure.
You should avoid caffeine (caffeinated as well as decaffeinated coffee, hot and cold tea, caffeinated soft drinks, energy drinks, chocolate and medications containing caffeine, etc.) and smoking for up to 48 hours before your examination. Your physician or radiologist may give you more specific instructions.
You should not eat or drink anything after midnight on the day of your procedure, but you may continue taking medications with small amounts of water unless your physician says otherwise. If you take beta-blocker or calcium channel blocker medication (Inderal, metoprolol, Norvasc, etc.) you should specifically ask your physician about temporary discontinuation. If you are diabetic, check with your physician about specific instructions for your diabetes medication on the day of the exam.
What will I experience during and after the procedure?
Except for intravenous injections, most nuclear medicine procedures are painless. They are rarely associated with significant discomfort or side effects.
When the radiotracer is given intravenously, you will feel a slight pinprick when the needle is inserted into your vein for the intravenous line. You may feel a cold sensation moving up your arm when the radiotracer is injected. Generally, there are no other side effects.
You will be asked to exercise until you are either too tired to continue or short of breath, or if you experience chest pain, leg pain, or other discomforts that causes you to want to stop.
If you are given a medication to increase blood flow because you are unable to exercise, the medication may induce a brief period of feeling anxious, dizzy, nauseous, shaky or short of breath. Mild chest discomfort may also occur. Any symptoms that do develop typically resolve as soon as the infusion is complete. In rare instances, if the side effects of the medication are severe or make you too uncomfortable, other drugs can be given to stop the effects.
It is important to remain still during the exam. Nuclear imaging itself causes no pain. However, having to remain still or to stay in one particular position during imaging may cause discomfort.
Unless your doctor tells you otherwise, you may resume your normal activities after your exam. A technologist, nurse or doctor will provide you with any necessary special instructions before you leave.
The small amount of radiotracer in your body will lose its radioactivity over time through the natural process of radioactive decay. It may also pass out of your body through your urine or stool during the first few hours or days following the test. Drink plenty of water to help flush the radioactive material out of your body.