Nuclear Medicine

What is Nuclear Medicine?

A Nuclear Medicine exam is a diagnostic procedure that uses a tracer substance and a special camera to detect energy in the form of gamma rays. It is often used to analyze kidney function, scan lungs for respiratory and blood-flow problems, check function of the heart, identify gallbladder blockage and evaluate bones.

The tracer substance, usually administered though a vein but sometimes given orally, contains a small amount of radioactive material that settles in a specific organ and gives off energy. The camera captures the energy and works with a computer to produce images and measurements of your organs and tissues. 

What are the Benefits of Nuclear Medicine?

  • Nuclear Medicine is a safe procedure with a very low incidence of side effects.
  • For many diseases, nuclear medicine studies provide information that is currently unavailable using other imaging procedures.
  • Nuclear Medicine is much less traumatic than exploratory surgery.

What are the Risks of Nuclear Medicine?

  • Nuclear Medicine has been used for more than thirty years and there are no known long-term adverse effects from this type of low-dose study.
  • Nuclear Medicine will result in some exposure to radiation through the tracer substance known as radiopharmaceutical. The does administered is the smallest amount possible.
  • Allergic reaction to the tracer substance can occur, but is extremely rare.
  • Women should always inform their doctor and the technologist if they are pregnant or think there is a possibility they may be pregnant. In general, exposure to radiation during pregnancy should be kept to a minimum.
  • Nursing mothers should wait 24 hours after tracer substance injection before resuming breast-feeding. 

What Will the Exam Be Like?

Depending on the study, the imaging may be done immediately, within a few hours or even a day or two after the tracer substance is received. This is because it can take several seconds to several days for the substance to travel through the body and accumulate in the organ to be studied.

For the imaging, you will be positioned as comfortably as possible on the examination table. If you think this position will be uncomfortable for you, inform the technologist as it will be very important for you to lie still during the exam. Any movement may result in the need to retake the scans. 

The special camera will then be used to detect the gamma rays, sending information to the computer to produce the images. The camera may be moved slowly along the body, or used to capture many different images and perhaps a few position changes to show how an organ functions over time. After the exam, a specialist trained in nuclear medicine will check the quality of the images.

A Nuclear Medicine exam typically takes about 20 to 45 minutes. 

Preparation for the Exam

  • If your exam involves your stomach, you may be asked to skip the meal before the exam.
  • If your exam includes your kidneys, you may be asked to drink plenty of water prior to the exam. 


  • Inform your doctor or technologist if you are undergoing radiation therapy.
  • Inform your doctor or technologist if you are allergic to iodine or other substance.
  • Always inform you doctor and the technologist if you are pregnant or think there is a possibility you may be pregnant.
  • Inform the technologist if you are sensitive to adhesive.

Nuclear Medicine Cardiac Stress Test

Why is the test done/ What is it for?

The cardiac stress test is used to find out if there is significant blockage of the blood supply to the heart (coronary artery disease). In this test, the doctor is looking at the heart muscle itself and the amount of radioactive material picked up (perfused) by the heart. This test gives doctors a good idea of what is going on in your heart.

Preparation for the Test

  • Do not eat or drink for four hours before the exam.
  • If you take insulin, you should talk to your doctor or clinic to change your dose for the day. If your drive is longer than three hours, it is okay to have a light breakfast of juice and toast before leaving home. If you use a blood sugar meter, please bring it along to the test.
  • If you will be having a drug stress test, or are unsure if you will be able to walk on the treadmill, do not have any caffeine 12 hours before the test. This includes coffee, tea, chocolate, and sodas with caffeine.
  • Bring pants or shorts that are easy to move in and soft-soled shoes.
  • Contact your doctor with questions about any drugs you are on for your heart or blood pressure. Your doctor will have to decide whether to stop them before the test. If you were told not to take certain drugs, bring them with you, and take them after the test.
  • You will be asked to sign a consent form for the exercise.
  • Bring a complete list of medicines you are currently taking.

The "Rest" Part of the Test

If you are claustrophobic and require medicine, please refer to your primary physician (PCP) for your needs. The "rest" images will be done before the stress test and will be compared with the others obtained after the stress part of the test.

For the "rest" images, a radioactive material that helps get pictures of your heart will be put through an IV line, and pictures will be taken 15-30 minutes later. You will be asked to lie flat on a table and remain still while the pictures are being taken. The machine moves slowly around your chest while you lie still. Each picture takes between 20-25 seconds and the entire scan is done in about 15-20 minutes.

The "Stress" Part of the Test

There are two ways the "stress" portion of the test can be done:

  • If you are able to walk about five blocks without pain, your heart can be stressed by walking on a treadmill. This workout will start out easy and slowly get harder. This is known as a treadmill stress test.
  • If you are not able to walk much, one of two drugs can be used to "stress" the heart. These will be given through an IV. This is known as a drug stress test.

For the stress test, small sticky pads will be placed on your chest. The contact of these pads to the skin is important to get a good signal. You may have some discomfort with the preparation of the skin for the pads. These pads will be hooked to an ECG monitor, so that your heart rate and rhythm can be watched closely throughout the test.

Your heart rate and blood pressure will be watched during the stress. Tell the person giving the test if you have any of these symptoms at any time:

  • Chest or arm pain
  • Shortness of breath

A radioactive material will be put through the IV line about 1 ½ minutes before the end of the stress test. It is carried to the heart by the blood where it is taken up by the heart muscle cells. The "stress" images will be taken 30-60 minutes after your stress test.

(This information is intended to serve as a simple guide. It can never replace the conversations with your own doctor. It is not a substitute for professional care.)