Fluorothymidine F-18

Fluorothymidine F-18 (also known as FLT F-18 or 18F-FLT) is a radiopharmaceutical used in positron emission tomography (PET) imaging. It is a fluorine-18 labeled analogue of the nucleoside thymidine, which is incorporated into the DNA of proliferating cells.

Chemistry

Fluorothymidine F-18 is a fluorinated analogue of the nucleoside thymidine. The fluorine-18 atom replaces a hydrogen atom on the methyl group of thymidine. This modification allows the molecule to be detected by PET imaging, as fluorine-18 is a positron emitter.

Pharmacology

Fluorothymidine F-18 is taken up by cells and phosphorylated by the enzyme thymidine kinase to form FLT-monophosphate. This molecule is then further phosphorylated to form FLT-diphosphate and FLT-triphosphate, which can be incorporated into DNA. The rate of FLT uptake and phosphorylation is proportional to the rate of cellular proliferation, making FLT F-18 a useful marker of tumor growth and response to therapy.

Clinical Use

Fluorothymidine F-18 is used in PET imaging to assess tumor proliferation in patients with various types of cancer, including lung cancer, breast cancer, and brain tumors. It can also be used to monitor the response of tumors to chemotherapy and radiation therapy. In addition, FLT F-18 can be used to assess the proliferation of normal tissues, such as the bone marrow and lymphoid tissues.

Safety and Side Effects

As with all radiopharmaceuticals, there is a risk of radiation exposure with the use of FLT F-18. However, the risk is generally low and is considered acceptable in the context of the potential benefits of the imaging procedure. Side effects are rare and typically mild, including allergic reactions and injection site reactions.

See Also

• Positron Emission Tomography
• Radiopharmaceutical
• Thymidine kinase
• Fluorine-18