______________ is similar in composition to glucose

______________ is similar in composition to glucose

• A. Thallium
• B. Fluorodeoxyglucose
• C. Iodine
• D. Technetium

Answer: (B)

Fluorodeoxyglucose is a glucose analog used in PET imaging. It mimics glucose closely enough to be taken up into cells by the same glucose transporters and then phosphorylated by hexokinase, just like glucose. However, once FDG is phosphorylated, it isn’t further metabolized efficiently, so it becomes trapped inside the cell as FDG-6-phosphate, allowing tissues with high glucose uptake to be visualized on PET scans. That glucose-analog behavior is what makes it the best choice for imaging metabolic activity, such as in cancer or inflammation. The other substances aren’t glucose-like molecules: thallium acts as a potassium analog for perfusion imaging, iodine is used for thyroid and other imaging, and technetium serves as a versatile radiometal in many radiopharmaceuticals, not as a glucose analog.

Fluorodeoxyglucose is a glucose analog used in PET imaging. It mimics glucose closely enough to be taken up into cells by the same glucose transporters and then phosphorylated by hexokinase, just like glucose. However, once FDG is phosphorylated, it isn’t further metabolized efficiently, so it becomes trapped inside the cell as FDG-6-phosphate, allowing tissues with high glucose uptake to be visualized on PET scans. That glucose-analog behavior is what makes it the best choice for imaging metabolic activity, such as in cancer or inflammation. The other substances aren’t glucose-like molecules: thallium acts as a potassium analog for perfusion imaging, iodine is used for thyroid and other imaging, and technetium serves as a versatile radiometal in many radiopharmaceuticals, not as a glucose analog.