Which of the following is a commonly used diagnostic radiopharmaceutical?

Technetium-99m (Tc-99m) is widely recognized as a commonly used diagnostic radiopharmaceutical due to its favorable properties for imaging purposes. It has a short half-life of about six hours, which allows for quick imaging without prolonged exposure to radiation. Additionally, Tc-99m emits gamma rays that are ideal for detection using gamma cameras, which are common in nuclear medicine.

The compound can be labeled with a variety of pharmaceutical agents, enabling specific targeting within the body for various diagnostic tests, such as bone scans, cardiac imaging, and thyroid assessments. Its versatility and the ability to conduct numerous types of scans makes it a staple of diagnostic radiopharmacy.

Other radiopharmaceuticals listed, while also used in various contexts, do not match the widespread usage of Tc-99m for routine diagnostic imaging. Carbon-14 is primarily utilized in research and carbon dating rather than medical diagnostics. Iodine-131 is mainly used for therapeutic purposes, especially in treating thyroid conditions, and its use as a diagnostic tool is less common. Strontium-90 is primarily used in radiation therapy and has limited application in diagnostics.