The purpose of this study is to evaluate the effectiveness of the Philips Sonalleve Magnetic Resonance Imaging-guided High Intensity Focused Ultrasound (MR-HIFU) device for treating painful bone metastases.

Magnetic Resonance Imaging-guided High Intensity Focused Ultrasound (MR-HIFU) is a non-invasive outpatient modality. In MR-HIFU, a specially designed ultrasound transducer is used to focus a beam of ultrasound energy into a small volume at a specific target site in the body. The focused beam is intended to produce therapeutic hyperthermia in the target field while only harmlessly warming the immediately surrounding tissue. Magnetic Resonance Imaging is used during the ultrasound treatment, both to focus the ultrasound beam on the target field and to perform real-time thermal mapping at and around the target.

The Philips Sonalleve MR-HIFU system is expected to be efficacious in reducing pain scores in patients with painful bone metastases and in reducing their pain medication usage.

Inclusion Criteria:

• Men and women with age ≥ 18 years
• Patient capable of giving informed consent and able to attend study visits
• Weight < 140kg
• Radiologic evidence of bone metastases from any solid tumor
• Diagnosis of dominant painful bone metastasis (Numerical Representative Scale (NRS) pain score ≥4), either refractory to standard of care (including radiotherapy and optimal pain medication) or standard of care is contra-indicated or refused by patient.
• Patient has been on stable pain medication for at least 1 week prior to HIFU treatment date
• Pain is localized to the targeted area, or is likely to be referred pain arising from the targeted area
• Patient has 1-3 painful lesions, and only the most painful lesion will be treated
• Intended Target Volume accessible for MR-HIFU procedure
• Target lesion maximum dimension ≤ 8cm
• Intended target volume visible by non-contrast MRI
• Distance between target and skin ≥ 1cm
• Patient is able to communicate sensation during MR-HIFU treatment
• MR-HIFU treatment date ≥ 4 weeks from last local treatment of the target lesion

Exclusion Criteria:

• Planned treatment lesion is a primary bone tumor or due to lymphoma, multiple myeloma, or leukemia.
• Communication barrier present
• Patient enrolled in another clinical study related to bone metastases treatment or pain relief treatment
• Unable to tolerate required stationary position during treatment
• Need for surgical stabilization in case of (impending) fracture (lytic lesion in weight-bearing bone larger than 50% of bone diameter)
• Pregnant woman
• Pain related to target lesion is predominantly due to fracture or impending fracture
• Pain related to target lesion is due to involvement of a neighboring major nerve by the metastatic tumor (cord or nerve compression)
• Target < 3cm from bladder / bowel / nerve along the beam path and < 1cm in the plane orthogonal to the beam
• Target in contact with hollow viscera
• Target located in skull, joints, ribs (when HIFU beam overlapping with lung), spine (excluding sacrum which is allowed) or sternum
• Scar along proposed HIFU beam path
• Internal or external fixation device along the proposed HIFU beam path or at the target
• MRI contraindicated (e.g. paramagnetic implants, pacemaker, claustrophobia)
• MRI contrast agent contraindicated (e.g. previous anaphylaxis or Glomerular Filtration Rate (GFR) < 30 ml/min/1.73m2)
• Sedation contraindicated
• Previous surgery or minimally invasive treatment at targeted site
• Clinically relevant medical history or abnormal physical findings that could interfere with the safety of the participant as judged by the treating physician or investigator