1. IRCIV, Institut Gustave Roussy, 114 Avennue Edouard Vaillant, 94805 Villejuif. France.
2. IR4M, UMR 8081, CNRS, Université Paris Sud 11, Orsay, France
3. Imaging Sciences Department, Imperial College, Hammersmith Hospital, London, UK
4. Oncology Department, Insitut Gustave Roussy, Villejuif, France