 FET PET scans will be performed before any procedure or surgical treatment and the data will be merged with MRI. The gold standard is histological examination or biopsy material, or complete resection of the tumor. A minimum of three biopsies per patient will be realized. The pathologist will not see the results of PET-FET 100 patients will be enrolled over a period of 5 years. The area under the curve will be determined on a non-parametric for each increase in the value of PET-FET at near 10th. The sensitivities, specificities, positive predictive values will be estimated with confidence intervals at 95. Factors to be considered in the analysis, the intrasubject variability related to the fact that several positive and negative results are found for each subject included. The concordance between the data-FET PET and MRI will be sought. 