Comparative Pharmacology
Head-to-head clinical analysis: FLUDEOXYGLUCOSE F18 versus SODIUM IODIDE I 123.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FLUDEOXYGLUCOSE F18 versus SODIUM IODIDE I 123.
FLUDEOXYGLUCOSE F18 vs SODIUM IODIDE I 123
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fludeoxyglucose F18 is a glucose analog that is taken up by cells via glucose transporters (GLUT), particularly GLUT-1. It is phosphorylated to FDG-6-phosphate by hexokinase, which cannot be further metabolized, leading to intracellular accumulation proportional to glucose metabolism. It emits positrons detected by PET imaging.
Sodium iodide I 123 is a radioactive isotope that emits gamma radiation. Following oral or intravenous administration, it is rapidly absorbed and selectively concentrated in the thyroid gland via the sodium-iodide symporter (NIS). The emitted gamma rays allow for imaging of thyroid tissue and detection of abnormal uptake patterns.
5-10 mCi (185-370 MBq) intravenous injection, single dose for PET imaging.
Oral: 400-800 μCi (14.8-29.6 MBq) for thyroid uptake studies; 150-300 μCi (5.6-11.1 MBq) for thyroid scan. Administer orally as a single dose.
None Documented
None Documented
Terminal elimination half-life is approximately 110 minutes (range 100–120 minutes). This reflects clearance of unmetabolized FDG from plasma and is clinically relevant for imaging timing, as optimal image acquisition occurs 30–60 minutes post-injection to allow for target-to-background ratio maximization.
13.2 hours (physical T1/2); effective T1/2 ~13 hours in euthyroid; prolonged in hypothyroidism.
Primarily renal; approximately 90% of injected activity is excreted unchanged in urine within the first 2 hours post-injection. Less than 5% is eliminated via feces.
Primarily renal (90%) as iodide; small amount feces (<5%) and negligible biliary.
Category C
Category C
Radiopharmaceutical
Radiopharmaceutical