What kind of radiation is emitted by radioactive isotopes such as Tc99m?

The correct choice is gamma radiation, which is emitted by radioactive isotopes like Technetium-99m (Tc-99m). Gamma rays are highly penetrating electromagnetic radiation that is produced during the decay of radioactive materials. Unlike alpha and beta radiation, which consist of particles (helium nuclei and electrons, respectively), gamma radiation is a form of energy that travels at the speed of light and can penetrate various materials, including human tissue.

Tc-99m is widely used in nuclear medicine for imaging studies because its gamma emissions allow for non-invasive visualization of physiological processes within the body. The energy from gamma radiation can be easily detected by gamma cameras, making it particularly useful for diagnostic imaging.

While alpha and beta radiation are associated with other types of radioactive decay, they are not the primary emissions from Tc-99m. Alpha particles are large and have low penetration capability, while beta particles, although more penetrating than alpha particles, do not relate to the imaging applications where gamma radiation excels. X-ray radiation is produced through different processes, typically involving electronic interactions rather than nuclear decay.

Understanding the nature of gamma radiation is crucial for those involved in nuclear medicine, as it informs both safety protocols and the effective use of radiopharmaceuticals.