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Nuclear heart scan overview

The two principal techniques used for nuclear heart scanning are single positron emission computed tomography (SPECT), and positron emission tomography (PET). In SPECT, the radiation given off by tracers is measured by the cameras rotating around the patient to image the heart from different angles. Two-dimensional images can be captured along the short axis, horizontal long axis, and vertical long axis of the heart, and can be compiled to reconstruct a 3-dimensional image.

PET functions similarly to SPECT, but employs different tracers and equipment. The exceptionally high energy of gamma rays produced during PET reduces scattering and improves image resolution. SPECT and PET are mainly employed to assess the blood flow through the myocardium, to evaluate the heart pumping function and to look for damaged heart tissue. Because cardiac conditions often remain subclinical when the patient is at rest, these diagnostic procedures are often combined with exercise stress testing.

There is no clear consensus as to which technique is superior, however, PET is generally acknowledged to allow for more detailed imaging, particularly through thick layers of abdominal or breast tissue.

Video Transcript

Nuclear heart scan overview - Animation

Nuclear heart scanning is a diagnostic imaging technique that relies on injection of a radioactive tracer near the patient’s heart. The tracer emits radiation in the form of gamma rays, which is imaged using specialized camera equipment. The two principal techniques used for nuclear heart scanning are single positron emission computed tomography (SPECT), and positron emission tomography (PET). In SPECT, the radiation given off by tracers is measured by the cameras rotating around the patient to image the heart from different angles. Two-dimensional images can be captured along the short axis, horizontal long axis, and vertical long axis of the heart, and can be compiled to reconstruct a 3-dimensional image. PET functions similarly to SPECT, but employs different tracers and equipment. The exceptionally high energy of gamma rays produced during PET reduces scattering and improves image resolution. SPECT and PET are mainly employed to assess the blood flow through the myocardium, to evaluate the heart pumping function and to look for damaged heart tissue. Because cardiac conditions often remain subclinical when the patient is at rest, these diagnostic procedures are often combined with exercise stress testing. There is no clear consensus as to which technique is superior, however, PET is generally acknowledged to allow for more detailed imaging, particularly through thick layers of abdominal or breast tissue.

Review Date: 4/10/2023

Reviewed By

Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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