MR-guided high-intensity focused ultrasound for noninvasive cancer treatment

Abstract

Magnetic resonance (MR)-high-intensity focused ultrasound (HIFU) is an innovative, noninvasive tumour ablation technique. MR imaging and focused ultrasound are combined allowing real-time anatomic guidance and temperature mapping during treatment. Recently, the volumetric ablation approach has been introduced in order to reduce treatment length and provide more homogeneous tumour ablation. After successful treatment of uterine fibroids, MR-HIFU is currently being investigated for the treatment of malignant tumours. Palliative treatment of painful bone metastases is already applied in clinical practice. Several issues need to be further investigated for successful cancer treatment with MR-HIFU, including patient selection criteria, definition of treatment margins and optimal transducer technology.

Figure 1

(a) Philips Healthcare clinical HIFU platform (Sonalleve) integrated into a 1.5-T Philips Achieva MR scanner. The arrow indicates the HIFU transducer embedded in the MR tabletop. (b) A close-up of the transducer is provided. The transducer consists of 256 piezoelectric elements (phased arrays).

Figure 2

MR-HIFU for palliative treatment of bone metastases. Radiograph (left) and MR image (right) of the left femur of a patient with a symptomatic bone metastasis secondary to renal cell carcinoma. The expansive lytic lesion was resistant to radiotherapy and therefore treated with MR-HIFU.