 The expected benefits are a better diagnostic ability of PET-FET which results in a specific targeting of biopsies with fewer tests to false negatives and false positives, thus a better diagnostic yield of this invasive procedure. Furthermore, the characteristics of this test applied to all of the tumor may help to better define the limit between healthy and tumor areas and thus reduce the radiation fields to the volumes strictly necessary. These volumes are currently defined on the results of the only morphological MRI and can be further clarified 