Which imaging modality uses a radioactive tracer to assess metabolic activity and is commonly used to locate tumors?

Which imaging modality uses a radioactive tracer to assess metabolic activity and is commonly used to locate tumors?

• A. Skull X-Ray
• B. Magnetic Resonance Imaging (MRI)
• C. Positron Emission Tomography (PET Scan)
• D. Myelography

Answer: (C)

The main idea here is imaging that shows how active tissues are metabolically, not just what they look like anatomically. A PET scan uses a small amount of radioactive tracer that behaves like glucose and accumulates in cells with high metabolic activity. Cancer cells typically consume more glucose, so they take up more tracer and appear as bright areas on the scan. This metabolic map helps locate tumors, assess how widespread cancer is, and monitor treatment response, often paired with a CT scan to place the metabolic information onto precise anatomy. The tracer’s radioactive decay is what the detector picks up as positrons emitted and annihilated, producing the signals that create the image. In contrast, other imaging methods mentioned rely on anatomy or structure alone: skull X-rays visualize bones, MRI uses magnetic fields to image soft tissues, and myelography uses contrast to outline the spinal canal—none of which provide metabolic activity through a radioactive tracer.

The main idea here is imaging that shows how active tissues are metabolically, not just what they look like anatomically. A PET scan uses a small amount of radioactive tracer that behaves like glucose and accumulates in cells with high metabolic activity. Cancer cells typically consume more glucose, so they take up more tracer and appear as bright areas on the scan. This metabolic map helps locate tumors, assess how widespread cancer is, and monitor treatment response, often paired with a CT scan to place the metabolic information onto precise anatomy. The tracer’s radioactive decay is what the detector picks up as positrons emitted and annihilated, producing the signals that create the image. In contrast, other imaging methods mentioned rely on anatomy or structure alone: skull X-rays visualize bones, MRI uses magnetic fields to image soft tissues, and myelography uses contrast to outline the spinal canal—none of which provide metabolic activity through a radioactive tracer.