18F-FLT

18F-FLT (3'-deoxy-3'-[18F]fluorothymidine) is a radiopharmaceutical used in positron emission tomography (PET) imaging. It is a thymidine analog that is utilized to measure cellular proliferation in various types of cancer.

Chemical Properties

18F-FLT is a synthetic nucleoside analog of thymidine, labeled with the radioactive isotope fluorine-18. The chemical structure of 18F-FLT allows it to be incorporated into the DNA of proliferating cells, making it a useful marker for imaging cell division.

Synthesis

The synthesis of 18F-FLT involves the nucleophilic substitution of a suitable precursor with fluorine-18. The process typically includes the use of automated synthesis modules to ensure high radiochemical purity and yield.

Mechanism of Action

18F-FLT is taken up by cells via the same transport mechanisms as thymidine. Once inside the cell, it is phosphorylated by thymidine kinase 1 (TK1), an enzyme that is upregulated in proliferating cells. However, unlike thymidine, 18F-FLT is not incorporated into DNA but is trapped within the cell after phosphorylation, allowing for imaging of cellular proliferation.

Clinical Applications

18F-FLT PET imaging is primarily used in oncology to assess tumor proliferation. It has been used in the evaluation of various cancers, including lung cancer, breast cancer, and lymphoma. The uptake of 18F-FLT in tumors can provide information on the aggressiveness of the cancer and the effectiveness of treatment.

Advantages and Limitations

Advantages

• Provides a non-invasive method to assess tumor proliferation.
• Can be used to monitor the effectiveness of cancer therapies.
• Offers higher specificity for proliferating cells compared to other PET tracers like 18F-FDG.

Limitations

• Limited by the availability of fluorine-18 and the need for specialized synthesis equipment.
• Lower sensitivity in detecting low-grade tumors compared to 18F-FDG.
• Uptake can be influenced by factors other than proliferation, such as inflammation.

Related Pages

• Positron emission tomography
• Radiopharmaceutical
• Fluorine-18
• Cancer
• Thymidine

See Also

• 18F-FDG
• Molecular imaging
• Oncology

External Links

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