[F-18]FLT-PET in oncology: current status and opportunities

In recent years, [F-18]-fluoro-3'-deoxy-3'-L-fluorothymidine ([F-18]FLT) has been developed as a proliferation tracer. Imaging and measurement of proliferation with PET could provide us with a non-invasive staging tool and a tool to monitor the response to anticancer treatment. In this review, the basis of [F-18]FLT as a proliferation tracer is discussed. Furthermore, an overview of the current status of [F-18]FLT-PET research is given. The results of this research show that although [F-18]FLT is a tracer that visualises cellular proliferation, it also has certain limitations. In comparison with the most widely used PET tracer, [F-18]FDG, [F-18]FLT uptake is lower in most cases. Furthermore, [F-18]FLT uptake does not always reflect the tumour cell proliferation rate, for example during or shortly after certain chemotherapy regimens. The opportunities provided by, and the limitations of, [F-18]FLT as a proliferation tracer are addressed in this review, and directions are given for further research, taking into account the strong and weak points of the new tracer.