Metastatic bone cancer and multiple myeloma affects over 600,000 people every year in the United States and cause progressive bone destruction that results in severe pain, fractures, and the inability to walk. Patients usually present with incapacitating pain secondary to osseous involvement, with or without vertebral collapse, and to spinal cord and/or nerve roots compression, commonly leading to paraplegia and quadriplegia. Conventional therapy consists of bed rest, bracing, anti-inflammatory, or narcotic analgesic medications, and radiation therapy. These conservative options (except radiation therapy) are not dissimilar from the management of osteoporotic compression fractures and are associated with the same type of complications, i.e., atelectasis and pneumonia, deep venous thrombosis and pulmonary embolism. Surgical options are not possible for all patients, but when indicated, they consist of heavy interventions such as corpectomy or cage placement, with significant postprocedural recovery periods and high morbidity and mortality rates in patients who often have limited life expectancies. In addition, multifocal vertebral lesions are common and may contraindicate surgery. Vertebroplasty affects the pain symptom and was not designed to treat cancer. Current options for local treatment of metastatic spine cancer are insufficient. The hypothesis is that thermal ablation with high intensity interstitial ultrasound (HIIU) specifically matched to the tumor size and shape can be safe and efficacious in the management of metastatic spine cancer. We propose to develop a mechanism to perform minimally invasive conformal ultrasound ablation under combined computer tomography (CT) and CT fluoroscopy (CTF) guidance. Our work indicates that this method may provide a consistent, reliable, and safe treatment option in a simple and cost-efficient manner. The unique aspect of our approach is the ability to destruct an asymmetric target volume with a single needle that does not need to be placed in the center of the lesion. Under CT/CTF image guidance, we insert the ablator, localize the ablator with respect to the target zone, and then electronically shape the energy output to conform the target. Thus moderate placement errors can be simply corrected electronically. We also can ablate difficult shapes located nearby sensitive structures. There is a strong clinical need to deliver a means to kill the tumor in a focused and safe way in this sensitive area, protecting the spinal cord, around which the tumor is likely to have caused significant bone destruction already. The ability to conform the energy to the shape of the tumor with a sharply defined fringe field is critical and would add very significant clinical value. This program will develop an integrated instrumentation - ablative treatment delivery system, establish safe and accurate percutaneous HIIU needle placement and tumor ablation under real-time quantitative CT/CTF guidance, develop appropriate clinical workflow, and demonstrate use in clinical application.