Use of [F-18] FLT for Imaging with Positron Emission Tomography (PET)

This pilot study will evaluate the use of [F-18] FLT and PET to measure tumor proliferation and the activity of thymidine kinase. This study may also assess the changes that occur after therapy. Finally we may compare the retention of [F-18] FLT in comparison to that of routine clinical measurements, such as CT, MRI or other imaging studies. One goal of this study is to better understand the abnormalities of thymidine metabolism in tumors in vivo. We may also compare imaging proliferation data using [F- 18] FLT to measurements of gene expression of proliferative and biochemical pathways made on tumor specimens obtained at biopsy.