PET scan uses which tracer material?
**Core Concept**
PET (Positron Emission Tomography) scan is a medical imaging technique that uses a radioactive tracer to visualize metabolic processes within the body. The tracer is a molecule that is labeled with a positron-emitting isotope, which allows for the detection of its distribution and concentration in the body.
**Why the Correct Answer is Right**
The most commonly used tracer material in PET scans is Fluorodeoxyglucose (FDG), a glucose analog that is taken up by cells in proportion to their metabolic rate. Once inside the cell, FDG is phosphorylated by hexokinase but not further metabolized, allowing for its detection by the PET scanner. The high uptake of FDG in cancer cells, due to their increased metabolic rate, makes it an ideal tracer for detecting and staging malignancies.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a commonly used PET tracer material.
* **Option B:** This option is incorrect because it is a type of X-ray contrast agent, not a PET tracer.
* **Option C:** This option is incorrect because it is a type of CT contrast agent, not a PET tracer.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that FDG PET scans are contraindicated in patients with elevated blood sugar levels, as the high glucose concentration can lead to false-negative results.
**Correct Answer: C. Fluorodeoxyglucose (FDG)**