Impact of the PET in the Diagnosis Strategy of FUO or Inflammatory Syndrome in Immunocompetent Patients FUO-TEP

Inclusion Criteria: * Patient with FUO criteria: Fever since 3 weeks, Temperature \> 38.3°C, No diagnostic after 3 days of hospitalization. * Patient with periodic fever criteria: Fever with criteria like FUO, Fever-free intervals, and apparent remission of the underlying disease, At least 3 febrile episodes. * Inflammatory syndrome without any clinical sign, Important inflammatory syndrome: Erythrocyte sedimentation rate ≥ 50 at the first hour, and elevation of at least one another inflammatory parameter (haptoglobin, orosomucoïd, fibrinogen or C-reactive protein), Evolution since more than 3 weeks, No diagnostic orientation after clinical examination and history-taking, No diagnostic clue after 3 days of hospitalisation. * Oral informed consent obtained. Exclusion Criteria: * Demented patient or unable to receive information on the protocol and to give informed consent. * Pregnant women, or without contraception. * Contraindication to iodine examination, gallium scintigraphy or 18FDG TEP-scan. * Immunodeficient patient. * Know HIV infection, neutropenic patient and nosocomial fever.