Positron Emission Tomography (PET) imaging uses an injection of a radionuclide attached to sugar to detect what characteristic of tumors?

Positron Emission Tomography (PET) imaging uses an injection of a radionuclide attached to sugar to detect what characteristic of tumors?

• A. To measure bone density
• B. To scan for metal implants
• C. To detect areas with high metabolic activity
• D. To assess blood flow via ultrasound

Answer: (C)

This question hinges on what PET imaging with a glucose-like tracer actually reveals. PET uses a radiolabeled sugar (FDG) that is taken up by cells in proportion to their glucose use. Cancer cells typically have higher glycolysis and more glucose transporters, so they take up more FDG and trap it inside. When the tracer is phosphorylated inside the cell, it can't exit easily, leading to a buildup that the PET scanner detects as bright zones. Those bright areas indicate regions of high metabolic activity, which often correspond to tumors. This is why PET highlights tumors by their metabolism, not bone density, metal implants, or blood flow measured by ultrasound. Keep in mind that inflammation can also show increased uptake, so clinicians correlate PET findings with other imaging and clinical information.

This question hinges on what PET imaging with a glucose-like tracer actually reveals. PET uses a radiolabeled sugar (FDG) that is taken up by cells in proportion to their glucose use. Cancer cells typically have higher glycolysis and more glucose transporters, so they take up more FDG and trap it inside. When the tracer is phosphorylated inside the cell, it can't exit easily, leading to a buildup that the PET scanner detects as bright zones. Those bright areas indicate regions of high metabolic activity, which often correspond to tumors. This is why PET highlights tumors by their metabolism, not bone density, metal implants, or blood flow measured by ultrasound. Keep in mind that inflammation can also show increased uptake, so clinicians correlate PET findings with other imaging and clinical information.