Which statement correctly lists the routes of administration for radiopharmaceuticals?

• A. Intravenous injection, inhalation, ingestion, and instillation
• B. Oral only
• C. Subcutaneous only
• D. Intramuscular only

Answer: (A)

Radiopharmaceuticals can be given through several administration routes, and each route serves different imaging needs by directing where the tracer goes and how quickly it distributes. Intravenous injection puts the tracer directly into the bloodstream, providing rapid systemic distribution and clear images of organs with good blood flow. Inhalation delivers the agent to the lungs, which is essential for ventilation/perfusion imaging and other lung studies. Ingestion allows the tracer to pass through the GI tract and be absorbed or localized in abdominal organs, useful for certain GI and hepatic imaging. Instillation introduces the radiopharmaceutical into a body cavity or lumen, giving localized activity for targeted imaging or functioning studies, such as in the bladder or other cavities, with minimal systemic exposure.

Choosing the option that includes all four routes correctly reflects the range of administration methods used in nuclear medicine. Limiting to a single route, as in the other statements, doesn’t capture how these tracers are actually used in practice.