Comparative Pharmacology
Head-to-head clinical analysis: FLUORINE F 18 versus SODIUM IODIDE I 123.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FLUORINE F 18 versus SODIUM IODIDE I 123.
FLUORINE F-18 vs SODIUM IODIDE I 123
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fluorine-18 decays by positron emission, and the emitted positron annihilates with an electron to produce two 511 keV gamma photons. When incorporated into radiopharmaceuticals such as fludeoxyglucose F-18, it accumulates in metabolically active tissues, enabling 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.
2-10 mCi (74-370 MBq) intravenous bolus, single administration 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
Physiological half-life is 109.7 minutes (1.83 hours) for fluorine-18 decay by positron emission, with a physical half-life of 109.7 minutes. The biological half-life is dependent on the radiolabeled compound; for [18F]FDG, the effective half-life is approximately 3-4 hours.
13.2 hours (physical T1/2); effective T1/2 ~13 hours in euthyroid; prolonged in hypothyroidism.
Primarily renal; approximately 95% of administered activity is excreted in urine within 6 hours post-injection. Less than 5% is excreted in feces.
Primarily renal (90%) as iodide; small amount feces (<5%) and negligible biliary.
Category C
Category C
Radiopharmaceutical
Radiopharmaceutical