Description:

16a-18F-fluoro-17b-estradiol ([18F]FES) is radioactive labeled estradiol, developed for in vivo visualization of the estrogen receptor (ER) using positron emission tomography (PET). To date, [18F]FES PET has been mainly explored as a diagnostic imaging tool to assess ER expression, thereby identifying locations of disease and their potential sensitivity to endocrine therapy, respectively. The primary aim of this project is to extend the application of [18F]FES PET as a baseline diagnostic imaging biomarker for ER expression to use it as an (early) treatment response marker. However, for such an application, visual assessment alone may not be sufficient and a more rigorous quantitative image analysis is needed. Therefore, in this project we shall first derive the optimal pharmacokinetic model for full quantitative analysis of [18F]FES uptake and, subsequently, we shall assess the validity of simplified, clinically feasible, quantitative parameters of [18F]FES uptake in 5 patients with metastatic estrogen receptor positive (ER+) breast cancer (part A). In addition, the repeatability of these simplified parameters will then be investigated in another 10 patients (part B).