Patient Information – Nuclear/PET | IAC

What is Nuclear Medicine?

Nuclear medicine is a medical specialty that is used to diagnose and treat diseases in a safe and painless way. Nuclear medicine procedures permit the determination of medical information that may otherwise be unavailable, require surgery, or necessitate more expensive and invasive diagnostic tests. The procedures often identify abnormalities very early in the progression of disease — long before some medical problems are apparent with other diagnostic tests. This early detection allows a disease to be treated sooner in its course when a more successful prognosis may be possible.

The information obtained through Nuclear Medicine examinations is extremely helpful to physicians in diagnosing a variety of conditions. It can be used to identify abnormal lesions, determine whether or not certain organs are functioning normally, and assess a patient’s blood volume, lung function, vitamin absorption, and bone density. In addition to identifying sites of seizures (epilepsy), Parkinson’s disease and Alzheimer’s disease, nuclear medicine can find cancers, determine whether they are responding to treatment, and determine if infected bones will heal. Specifically, Nuclear Cardiology studies use noninvasive techniques to assess myocardial blood flow, evaluate the pumping function of the heart, as well as visualize the size and location of a heart attack. A specific type of nuclear medicine procedure called a PET (Positron Emission Tomography) scan is rapidly becoming a highly reliable tool in determining the presence and severity of cancers, neurological disorders and cardiovascular disease. In addition to diagnostic imaging, nuclear medicine can be used as medical therapy to treat diseases such as hyperthyroidism, certain types of cancers (lymphomas) and to manage bone pain as a result of cancer.

Early detection of life-threatening heart disorders and other diseases is possible through the use of nuclear medicine procedures performed within hospitals, outpatient centers and physicians’ offices. Nuclear medicine’s reliability in diagnosing vast types of diseases and heart conditions is encouraging as we strive for ways to reduce lives lost in the United States each year. However, it is critical that the public realizes there are many facets that contribute to an accurate diagnosis based on nuclear medicine. These factors include the skill of the nuclear medicine technologist performing the examination, the type of equipment used, the background and knowledge of the interpreting physician and quality assurance measures. In fact, poor nuclear medicine procedures often lead to inconvenient, redundant studies, misdiagnosis and even unnecessary tests or surgery.

Types of Nuclear Medicine Exams

Use the links below to learn more about the different types of vascular exams.

  • Nuclear Cardiology (Myocardial Perfusion Imaging): A myocardial perfusion scan is a nuclear medicine procedure used to assess the blood flow to the heart muscle both at stress and at rest. The two images are compared to each other to allow an assessment of damage to the heart muscle or a lack of enough blood flow to the heart muscle during exercise. The test is usually ordered by a physician to assess chest pain or other symptoms that may be related to the heart.
  • Nuclear Cardiology (Equilibrium Radionuclide Angiography): Equilibrium Radionuclide Angiography (ERNA) is a type of nuclear medicine test used to evaluate the function of the heart ventricles. It is also called a MUGA scan (Multi Gated Acquisition). It provides a movie-like image of the beating heart, and allows the doctor to determine the health of the heart’s major pumping chambers. The advantages of an ERNA or MUGA scan is that it is more accurate than an echocardiogram and it is noninvasive. The scan involves the introduction of a radioactive marker into the bloodstream of the patient. The patient is subsequently scanned to determine the circulation dynamics of the marker, and hence the blood.
  • General Nuclear Medicine (Gastrointestinal System; Central Nervous System; Endocrine System; Musculoskeletal System; Genitourinary System; Pulmonary System; Infectious Disease Processes; Tumors; Nuclear Medicine Therapy): Radiopharmaceuticals are introduced into the patient’s body by injection, swallowing, or inhalation. The amount given is very small. The pharmaceutical part of the radiopharmaceutical is designed to go to a specific place in the body where there could be disease or an abnormality. The radioactive part of the radiopharmaceutical that emits radiation, known as gamma rays (similar to x-rays), is then detected using a special camera called a gamma camera. This type of camera allows the nuclear medicine physician to see what is happening inside the patient’s body. During this imaging procedure, the patient is asked to lie down on a bed and then the gamma camera is placed a few inches over the patient’s body. Pictures are taken over the next few minutes.
  • Positron Emission Tomography (PET): PET images demonstrate the chemistry of organs and other tissues such as tumors. A radiopharmaceutical, such as FDG (fluorodeoxyglucose), which includes both sugar (glucose) and a radionuclide (a radioactive element) that gives off signals, is injected into the patient and its emissions are measured by a PET scanner. A PET scanner consists of an array of detectors that surround the patient. Using the gamma ray signals given off by the injected radionuclide, PET measures the amount of metabolic activity at a site in the body and a computer reassembles the signals into images. Cancer cells have higher metabolic rates than normal cells, and show up as denser areas on a PET scan. In addition, PET is useful in diagnosing certain cardiovascular and neurological diseases because it highlights areas with increased, diminished, or no metabolic activity, thereby pinpointing problems. PET is a medical imaging modality that inspects all organ systems of the body, enabling it to search for cancer in a single examination. PET’s ability to measure metabolism also has significant implications in diagnosing Alzheimer’s disease, Parkinson’s disease, epilepsy and other neurological conditions, because it can vividly illustrate areas where brain activity differs from the norm.

Excerpts of this information are taken, with permission, from the following sources (each sponsoring organizations of the IAC Nuclear/PET):

  • Reprinted by permission of the Society of Nuclear Medicine from “What Is Nuclear Medicine?” Patient Pamphlet.
  • The World Molecular Imaging Society’s (formally the Academy of Molecular Imaging) copyrighted, printed patient information brochure entitled “Power of Molecular Imaging.”