MR guided High Intensity Focused Ultrasound for tumor ablation in brain: preliminary results

Introduction Brain therapy with transcranial focused ultrasound is a scientific and technological challenge [1,2]. A novel prototype is presented here (SuperSonic Imagine, France), working at the highest frequency envisioned currently for transcranial brain treatment (1MHz). A non invasive time-reversal focusing technique based on CT scans is performed for that purpose [3]. Such a brain therapy device operating at 1MHz should be particularly suited for well defined targets such as metastases and essential tremors. Thanks to the ability of MR to provide temperature maps with a good accuracy every few seconds, ultrasonic ablation of tissues has been implemented clinically and used successfully for the treatment of uterine fibroids [4]. The aim of this study was twofold. The first goal was to check if the new prototype was fully MR-compatible. The second aim was to heat a PVA-gel, and ex vivo brain tissues, directly or through a human skull. The changes in temperature were monitored with MRI.