18F-16 alpha-fluoroestradiol

A radiolabeled form of estradiol used in medical imaging

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18F-16 alpha-fluoroestradiol

Drug Information
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Identifiers ATC Code DrugBank KEGG ChEBI		Chemical Data N Molecular Weight

18F-16 alpha-fluoroestradiol (18F-FES) is a radiolabeled form of the hormone estradiol, which is used in positron emission tomography (PET) imaging to evaluate estrogen receptor (ER) status in various cancers, particularly breast cancer.

Chemical Structure and Properties

18F-16 alpha-fluoroestradiol is a synthetic analog of estradiol, where a fluorine-18 atom is substituted at the 16-alpha position. This modification allows the compound to be used as a radiotracer in PET imaging. The fluorine-18 isotope is a positron emitter, which is ideal for PET due to its relatively short half-life of approximately 110 minutes.

Mechanism of Action

18F-FES binds to estrogen receptors in the body, mimicking the natural hormone estradiol. When administered to a patient, it accumulates in tissues that express estrogen receptors, such as certain types of breast cancer cells. The radiolabeled compound emits positrons, which are detected by the PET scanner, allowing for visualization of ER-positive tissues.

Clinical Applications

The primary use of 18F-FES is in the imaging of breast cancer to assess the presence and distribution of estrogen receptors. This information can be crucial for determining the appropriate treatment strategy, as ER-positive cancers may respond well to hormone therapies such as tamoxifen or aromatase inhibitors.

18F-FES PET imaging can also be used in other estrogen receptor-positive cancers, such as some types of endometrial cancer and ovarian cancer.

Advantages and Limitations

Advantages

• Provides a non-invasive method to assess ER status in tumors.
• Can help guide treatment decisions and monitor therapy response.
• Offers whole-body imaging, which can detect metastatic disease.

Limitations

• Limited availability due to the need for specialized facilities to produce the radiotracer.
• Short half-life of fluorine-18 requires rapid imaging after administration.
• Not all ER-positive tumors may be detected due to variability in receptor expression.

Safety and Side Effects

18F-FES is generally well-tolerated, with minimal side effects. The radiation dose from the PET scan is relatively low, but as with any radiopharmaceutical, it is important to minimize exposure, especially in pregnant or breastfeeding women.

Also see

• Estradiol
• Estrogen receptor
• Positron emission tomography
• Breast cancer
• Radiopharmaceutical