Which type of scan is typically used to show metabolically active tissue in malignant masses?

The choice of a PET scan is appropriate because this imaging technique is specifically designed to detect metabolic activity in tissues. Malignant tumors often have increased metabolic rates compared to normal tissues, making them more visible during a PET scan. The scan uses a radioactive tracer that highlights areas of high metabolic activity, which is typical in cancerous tissues.

In contrast, X-Rays primarily provide structural images and are not effective at assessing metabolic processes. CT scans offer detailed cross-sectional images of the body and can show structural anomalies, but they do not differentiate between the metabolic activity of tissues. MRI is excellent for soft tissue imaging and also provides structural information, yet it, too, falls short in visualizing metabolic activity the way a PET scan does. Therefore, for identifying metabolically active malignant masses, the PET scan stands out as the most effective imaging modality.