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Magill’s Medical Guide, 9th Edition

Nuclear radiology

by Elizabeth Lynn, , MD, Leonard Ong, , MD

Category: Procedure

Also known as: Nuclear medicine

Anatomy or system affected: Bones, brain, glands, kidneys, musculoskeletal system, nervous system

Specialties and related fields: Nuclear medicine, radiology

Definition: The use of radiopharmaceuticals for the diagnosis of disease and the assessment of organ function.

Key terms:

collimator: a device that directs photons into a crystal for their detection

gamma camera: a system composed of a cesium-iodide crystal, collimator, and computer which is used to detect radioactivity and create an image of its distribution

radioisotope: a radioactive atom

radiopharmaceutical: the combined form of a pharmaceutical labeled with a radioisotope

INDICATIONS AND PROCEDURES

Nuclear radiology, also known as “nuclear medicine,” is a subspecialty of radiology that uses radiotracers to look at various functions of the human body. Radiotracers are molecules that are tagged with a small amount of radioactive isotope. Depending on the radiotracers that is used, these radioactive molecules have affinities to certain parts of the body (such as bone, heart, kidney, thyroid, brain). The most common radiotracer is FDG (F-18 fluorodeoxyglucose), which is radioactive glucose. Glucose can be thought of as a source of sugar that the body turns into energy. Since cancer cells metabolize sugar for its accelerated cell division, FDG is used to identify lesions that are suspicious for cancer.

USES AND COMPLICATIONS

Positron emission tomography/Computed tomography (PET/CT) scans are used to locate possible cancer and metastasis. Metastasis is the process or ability of the primary cancer to spread to distant parts of the body.

Bone scintigraphy (also known as a “bone scan”) can locate bone infection (e.g., osteomyelitis), bone cancers (both primary or metastases), or fractures.

Myocardial perfusion imaging can show the function of the heart muscle. The imaging is done at rest and then again after exercise. If the radiotracers are not picked up by a section of the heart after exercise, but was picked up by that same section of the heart at rest, it represents ischemia (i.e., a lack of oxygen to the heart muscles). This can help determine if cardiac surgery is indicated to revascularize the heart muscle.

Thyroid uptake scan is used to determine thyroid function. This can help evaluate nodules, goiters, or if the thyroid has hyperfunction (i.e., Graves’ disease) or hypofunction (i.e., hypothyroidism).

An RNC Nuclear scan tags red blood cells (RBCs) with radiotracers to locate bleeding sites in the gastrointestinal tract (the stomach and intestines).

Risks of nuclear medicine include radiation risk and allergic reactions. A very small dose of radiotracers are used during these imaging and are considered a low radiation exposure that does not lead to known long-term adverse affects. Allergic reactions are rare and usually mild.

PERSPECTIVE AND PROSPECTS

Artificially produced radionuclides were thought to be discovered by Frederic Joliot-Curie and Irene Joliot-Curie (also known as Madame Curie) in 1934. In 1946, the first thyroid cancer was successfully treated with radioactive iodine. However, it was not until 1950s that nuclear medicine was widely used. Today, nuclear medicine is used for the diagnosis and treatment of many diseases. This field of medicine continues to advance. Recently, Florbetapir F18 became the first US Food and Drug Administration (FDA)-approved imaging agent that can be used to identify Alzheimer’s disease. Prior to this, Alzheimer’s disease was only confirmed through postmortem (i.e., after death) identification of neurofibrillary tangles in the brain.

See also: Biophysics; Imaging and radiology; Magnetic resonance imaging (MRI); Nuclear medicine; Positron emission tomography (PET) scanning; Radiation therapy; Radiopharmaceuticals.

For Further Information:

1 

American College of Radiology and Radiological Society of North America. “Radiology Information for Patients.” RadiologyInfo.org for Patients. General Nuclear Medicine, 2018, www.radiologyinfo.org/en/info/gennuclear. Accessed 10 Apr. 2022.

2 

Freudenrich, C. How Nuclear Medicine Works. HowStuffWorks, science.howstuffworks.com/nuclear-medicine.htm. Accessed 10 Apr. 2022.

3 

Society of Nuclear Medicine and Molecular Imaging. “Fact Sheet: What Is Nuclear Medicine and Molecular Imaging?” SNMMI. Accessed 10 Apr. 2022.

Citation Types

Type
Format
MLA 9th
Lynn, Elizabeth, and Leonard Ong. "Nuclear Radiology." Magill’s Medical Guide, 9th Edition, edited by Anubhav Agarwal,, Salem Press, 2022. Salem Online, online.salempress.com/articleDetails.do?articleName=MMG2022_0966.
APA 7th
Lynn, E., & Ong, L. (2022). Nuclear radiology. In A. Agarwal, (Ed.), Magill’s Medical Guide, 9th Edition. Salem Press. online.salempress.com.
CMOS 17th
Lynn, Elizabeth and Ong, Leonard. "Nuclear Radiology." Edited by Anubhav Agarwal,. Magill’s Medical Guide, 9th Edition. Hackensack: Salem Press, 2022. Accessed October 22, 2025. online.salempress.com.