Nuclear Medicine & Imaging

What is Nuclear Medicine?

A Nuclear Medicine study assesses organ function and identifies the presence of disease. The study uses small amounts of radioactive substances known as tracers, which are designed to target and image a specific area of the body.

This type of imaging is performed by a Nuclear Medicine Technologist (a technologist who is trained in Nuclear Medicine) and  a Nuclear Medicine Physician (a doctor who specialises in Nuclear Medicine).

Nuclear Medicine imaging equipment is very specialised and is available at Ruby Hall Clinic.

Is nuclear medicine safe?

Nuclear medicine procedures are among the safest diagnostic imaging exams available. A patient only receives an extremely small amount of a radiopharmaceutical, just enough to provide sufficient diagnostic information. In fact, the amount of radiation from a nuclear medicine procedure is comparable to, or often times less than, that of a diagnostic x-ray.

Although we don’t think much about it, everyone is continually exposed to radiation from natural and manmade sources. For most people, natural background radiation from space, rocks, soil, and even carbon and potassium atoms in his or her own body, accounts for 85 percent of their annual exposure. Additional exposure is received from consumer products such as household smoke detectors, color television sets, and luminous dial clocks. The remainder is from x-rays and radioactive materials used for medical diagnosis and therapy. With most nuclear medicine procedures, the patient receives about the same amount of radiation as that acquired in a few months of normal living.

How is the procedure performed?

You are given a small dose of radioactive material, usually intravenously but sometimes orally, that localizes in specific body organ systems. This compound, called a radiopharmaceutical or tracer, eventually collects in the organ and gives off energy as gamma rays. The gamma camera detects these rays and works with a computer to produce images and measurements of organs and tissues.

After the radiopharmaceutical is administered, depending on which type of scan is being performed, the imaging will be done either immediately, a few hours later, or even several days after it’s administration. Imaging time varies, generally ranging from 20 to 45 minutes.

The radiopharmaceutical that is used is determined by what part of the body is under study since some compounds collect in specific organs better than others. Depending on the type of scan, it may take several seconds to several days for the substance to travel through the body and accumulate in the organ under study, thus the wide range in scanning times.

While the images are being obtained, you must remain as still as possible. This is especially true when a series of images are obtained to show how an organ functions over time.

After the procedure, a physician with specialized training in nuclear medicine checks the quality of the images to ensure that an optimal diagnostic study has been performed.

Some Common Nuclear Medicine Tests

Stress thallium

This procedure is used to diagnose the presence of coronary artery disease. Usually you exercise on a tread mill while a radioactive compound called thallium is injected into your bloodstream. The thallium is then absorbed by the walls of your heart. Imaging is begun immediately after exercising and then again 3-4 hours later.

Stress Thallium

Bone Scan

Bone scans are used to detect areas of bone fractures, tumors, bone infections, arthritis, etc. A radioactive compound is injected into your bloodstream and is absorbed by the bones.
Imaging is done two hours later. Usually the entire body is scanned, although it may sometimes require just the area in question.

Metastatic Disease in Bone Scan


You have been scheduled for a Renal Study with Lasix which involves the use of a small amount of radioactive material. You will be positioned next to a special detector called a gamma camera (see photo). The camera does not produce any radiation. It will be placed close to the part of your body being imaged

Lung Scan

Used primarily to detect pulmonary embolism (blood clots in the lung). This study is done in two phases. First, you inhale a radioactive gas that lines the tissues of the lungs. Then a series of images  are acquired. This phase shows how well your lungs are ventilating. Next, a radioactive compound is injected into your bloodstream and more images are taken. This phase checks the blood supply to your lungs. Imaging time is approximately one hour.

Liver Scan

Used to diagnose liver disorders such as cirrhosis or tumors. A radioactive compound is injected into your bloodstream and absorbed by the liver.
Various images are taken 15-20 minutes later. Imaging time is approximately 20 minutes.

Liver Scan

Thyroid Imaging and Function

Used to diagnose disorders of the thyroid gland. For the function study a capsule containing radioactive iodine is swallowed and absorbed by the thyroid gland. You return 24 hours later to see how much of the iodine was absorbed. This measurement

determines how active the thyroid gland is. Thyroid
imaging is used to check the size and shape of the
gland and to localize nodules or tumors. Imaging
time is approximately 20 minutes.

Thyroid Scan – Hyperthyroidism


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