Nuclear medicine is the medical specialty that either uses minute amounts of radioactive substances to study the body or uses special types of radioactivity to treat disease, such as an overactive thyroid, thyroid cancer, or lymphoma. Nuclear medicine tests - among the safest diagnostic imaging exams available - are virtually painless (a minor needle stick in a vein), cost-effective, and less traumatic than exploratory surgery. These studies provide information about both body structure (anatomy) and function (physiology) to help physicians determine the cause of a medical problem, often very early in the course of a disease before it would be apparent by other diagnostic tests.

Before the test, the patient is given a minute dose of radioactive material by injection, swallowing, or inhalation. Unless intended to treat disease, the amount of radioactivity is too small to have a measurable effect on the body.  This material eventually concentrates in a specific body organ and gives off energy as gamma rays (similar to x-rays). A special camera detects the rays and transmits the information to a computer that produces images and measurements of organs and tissues. A board-certified physician who has specialized training in nuclear medicine supervises the procedure, interprets the images, and reports the results to the patient’s physician.

Depending on the type of scan being performed, the imaging will be done either immediately or a few hours to several days later. Imaging time varies, generally ranging from 20 to 45 minutes. The amount of radiation given to the patient is very low - similar to that with standard x-rays – and poses little or no risk. Allergic reaction to the radiopharmaceutical material is extremely rare; indeed for PET scanning an allergic reaction has never been observed in the several million patients so examined.

An innovative nuclear medicine procedure, Positron Emission Tomography (PET), has become a major diagnostic tool and is particularly effective in identifying whether cancer is present or not, if it has spread, and if it is responding to treatment. Studies show that by imaging biochemical activity, PET can also accurately characterize a tumor as benign or malignant, avoiding surgical biopsy when the PET scan is negative. PET is often used in conjunction with a CT or MRI to give a full three-dimensional view of an organ and the location of cancer within that organ.

PET technology is based on how a patient’s disease uses sugar. PET images are created when a radiopharmaceutical which includes sugar (glucose) that has been made radioactive, which is injected into the patient.  The emissions are measured by a PET scanner. Newer PET scanners are a combination of PET/CT devices, and PET/MRI scanners are being developed.

For many diseases, nuclear medicine provides the most useful information to make a diagnosis and determine appropriate treatment. At UAMS Medical Center, nuclear medicine studies are typically used to:

Analyze kidney function
Detect/treat an overactive or underactive thyroid
Determine the presence or spread of cancer
Treat cancer (especially thyroid cancer or Non-Hodgkin’s Lymphoma)
Diagnose Alzheimer's disease, Parkinson's disease, epilepsy, and other neurological conditions
Evaluate bones for fracture, infection, arthritis or tumor
Identify gallbladder blockage
Image blood flow and heart function
Locate the presence of infection
Scan lungs for respiratory and blood-flow problems (such as blood clots)

More information about nuclear medicine may be found at these websites.
www.radiologyinfo.org
www.snm.org