F-18 16 Alpha-Fluoroestradiol

**Semantic type:** Indicator, Reagent, or Diagnostic Aid|Pharmacologic Substance

**Definition:** A radiopharmaceutical consisting of an estradiol analogue radiolabeled with the positron-emitting isotope fluorine F 18. F-18 16 alpha-fluoroestradiol is actively taken up in tumor cells expressing the estrogen receptor (ER), allowing visualization of ER-positive tumor cells with positron emission tomography (PET). Uptake of this agent depends upon the ER status of target tissues.

**Synonyms:** - 16 alpha-fluroestradiol-17 beta - F-18 16 alpha-fluoroestradiol - F-18 FES - F-18 FES - FES - FLUOROESTRADIOL F-18 - Fluorine-18 16 alpha-fluoroestradiol - Fluoroestradiol F-18