What is the primary type of radiation emitted by radioactive isotopes used in medical imaging?

The primary type of radiation emitted by radioactive isotopes used in medical imaging is gamma radiation. This is because gamma rays are high-energy photons that can penetrate tissues and are emitted during the radioactive decay of isotopes in a medical setting, such as technetium-99m.

Gamma radiation is particularly useful in imaging procedures, such as PET scans or SPECT scans, because it provides high-resolution images and allows for the visualization of physiological processes inside the body. The ability of gamma rays to traverse body tissues enables them to be detected by external sensors, producing clear images that are essential for diagnostic purposes.

In contrast, while alpha and beta radiation are also forms of radioactive decay, they have limitations in medical imaging. Alpha particles, for example, have low penetration power and cannot travel through human tissue, making them unsuitable for imaging. Beta radiation can penetrate tissue more than alpha particles but still lacks the ideal properties that gamma rays provide for imaging. X-rays, while also used in imaging, are produced through different mechanisms unrelated to radioactive decay and are not emitted by radioactive isotopes used for medical purposes. Therefore, gamma radiation is specifically favored in this context for its effectiveness and safety.