Which radioisotope is most commonly used in medical imaging?

• A. Carbon-14
• B. Iodine-123
• C. Technetium-99m
• D. Cesium-137

Answer: (C)

Technetium-99m is the most commonly used radioisotope in medical imaging due to its ideal properties that make it particularly suited for diagnostic procedures. It has a half-life of about six hours, which allows it to decay quickly enough to limit radiation exposure to patients while still providing sufficient time for imaging. This radioisotope emits gamma rays that can be detected by gamma cameras, producing clear images of organs and tissues.

Additionally, Technetium-99m has a range of available radiopharmaceuticals and can be easily bound to various molecules, enabling targeted imaging for different medical conditions. Its widespread use in procedures such as single-photon emission computed tomography (SPECT) contributes significantly to its popularity in the medical field.

The other options listed are less suited for medical imaging: Carbon-14 is primarily used for radiocarbon dating rather than medical diagnostics. Iodine-123 is used for thyroid imaging but is not as broadly applicable as Technetium-99m. Cesium-137 is used in radiation therapy and industrial applications rather than diagnostic imaging due to its longer half-life and higher radiation dose to patients.