MRI-guided Focused Ultrasound : Feasibility Study for the Treatment of Bone Metastases and osteoïd Osteoma

Ufoguide is a prospective single arm open study to assess the feasibility of a new type of HIFU system for the treatment of painful metastases (palliative intent) and osteoid osteoma (curative intent). HIFU is classically delivered by a transducer integrated in the MRI table. This study assesses a new type of approach in which the HIFU transducer is manually placed on the skin of the patient and held in place by MR-compatible passive arms. Optical infrared navigation is used to help the physician with the positioning of the HIFU transducer. The primary goal of this study is to assess the feasibility of heating the tumor accurately with this new HIFU system. The evaluation and control of the treatment will be performed by Proton Resonance Frequency Shift (PRFS) MR thermometry. Secondary endpoints include the evaluation of clinical efficacy, quality of life and safety. Clinical efficacy is defined: * in palliative intent by a decrease ≤3 on visual analogic scale * in curative intent (osteoid osteoma) by a total disappearance of pain Quality of life is assessed by EORTC quality of life questionnaire-core 30 items Complications are recorded to assess safety.