Which imaging modality uses radioactive pharmaceuticals such as technetium?

• A. Ultrasound
• B. Scintigraphy
• C. MRI
• D. CT

Answer: (B)

Nuclear medicine imaging uses radioactive pharmaceuticals such as technetium to visualize how organs and tissues function. In this approach, a tracer labeled with technetium is given to the patient and travels to specific tissues based on biology. The tracer emits gamma rays, which are detected by specialized cameras to create images that reflect physiology—like blood flow, metabolism, or uptake patterns. This is different from ultrasound, which uses sound waves; MRI, which uses magnetic fields and radiofrequency signals; and CT, which relies on X-ray attenuation to show anatomy. Because the key feature here is the use of a radiopharmaceutical to generate functional images, this modality is the one that uses technetium.