Hungarian Radiology

[MR-guided ultrasound surgery]

JÓLESZ Ferenc A., BÉRCZI Viktor, HÜTTL Kálmán, REPA Imre, KULLERVO Hynynen

JUNE 20, 2002

Hungarian Radiology - 2002;76(03)

[The powerful union of focused ultrasound surgery and magnetic resonance imaging has created a new approach to noninvasive surgery. Using this integrated therapy delivery system the physician can achieve correct localisation of tumors, optimal targeting of acoustic energy, real time monitoring of energy deposition, and the means to accurately control the deposited thermal dose within the entire tumor volume. The advantages of MRI over ultrasound guidance in controlling focused ultrasound surgery lie in the more sensitive detection of tumor target, the real time detection of tissue temperature, and the confirmation of thermally-induced tissue changes - powerful features that eventually can replace the traditional surgical approach. Applying software that connects the therapy and imaging system, the physician can generate an entire plan from quantifying temperature changes to positioning the therapy transducer. The non-invasive debulking of tumors without disturbing adjacent, functionally intact structures is thereby accomplished. Ongoing clinical trials involving the treatment of breast fibroadenoma, localized breast cancers, and uterine fibroids have been most encouraging. But nowhere has the application of MRI-guided focused ultrasound surgery been more compelling than in brain, where not only tumor treatment is possible but also the focal, transient, reversible breakdown of the blood-brain-barrier. The implications of this mechanism for targeted intra-cerebral tumor therapy or other non-oncologic applications are clearly enormous. In addition to tumor treatment, MRI-guided focused ultrasound surgery has other potential clinical applications such as vascular occlusion, targeted drug delivery, and targeted gene therapy. FUS is not a new idea but the emergence of MRI based guidance has accelerated the progres of focused ultrasound surgery technology, certain weaknesses remain including excessively long treatment times, body and organ motion, and difficulties in finding acoustic windows at certain anatomic locations. Nevertheless, the successful clinical implementations of this method is already in progress.]

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