Treatment of Opioid-refractory Pain (WHO Level III) by Pituitary Radiosurgery

Inclusion Criteria: * Man or woman, aged 18 years or older; * Subject suffering from nociceptive or mixed pain, not related to acts, refractory to standard opioid therapy * Subject having a cancer defined by histology whatever the origin of the primitive cancer, * Subject having multiple bone metastases * Subject in palliative care state according to the definition given by the French Society of Palliative Care and Support * Subject supported by structures of palliative care, pain or cancer involved in the study * Inpatient and outpatient * Subject without a curative cancer treatment and with or without palliative anticancer treatment; * Subject non in "ultimate" phase (estimated survival superior at 48 h by a physician) * Subject with acceptable general condition (Karnofsky performance Status Scale superior at 40 * Subject with a preserved vigilance defined from the Epworth scale * Subject with preserved cognition according to the scale Basic Test Concentration, Memory and Guidance (TELECOM) * Subject which can fill in a questionnaire, able to read or to understand the French language; * Subject who signed an informed consent; * Subject affiliated to the French health insurance system. Exclusion Criteria: * Subject with a curative cancer treatment * Subject in "ultimate" phase (estimated by the physician of survival less than 48 hours) * History of whole brain radiation * History of radiosurgery of pituitary lodge * Subject treated there less than a month by external or metabolic radiotherapy analgesic, surgical analgesic technic * Subject minor, pregnant or breastfeeding, subject not being affiliated to the French health insurance system or private about freedom; * Subject refusing to participate in the study or not signing the informed consent. * Subject allergic to any component of Fludeoxyglucose (18F) * Subject allergic to gadolinium salts. * Subject with severe renal impairment