What distinguishes a radioisotope from a radiopharmaceutical?

The distinction between a radioisotope and a radiopharmaceutical lies in their definitions and applications. A radioisotope is a variant of a chemical element that has an unstable nucleus and emits radiation during its decay process. In contrast, a radiopharmaceutical is a medicinal formulation that contains a radioisotope along with other components, typically designed for medical uses such as diagnosis or therapy.

This difference is crucial because a radioisotope can exist independently and may be used in various fields, including scientific research, industrial applications, or healthcare, but it does not inherently possess a therapeutic or diagnostic purpose until it is combined with appropriate pharmaceutical components and formulated as a radiopharmaceutical.

Thus, while a radioisotope can be a building block within a radiopharmaceutical, the latter serves a specific medical function by integrating the radioactive element into a compound that can be utilized in clinical settings, such as imaging or treating diseases.