MRgHIFU Safety Issue: Validation of Targeting Accuracy using an MR Compatible Ballistic Model

Magalie Viallon¹, Lorena Petrusca¹, Sylvain Terraz¹, Thomas Goget¹, Vincent Auboiroux¹, Christoph Becker¹, Patrick Gross², Rares Salomir¹

Fast volumetric ablation (5 to 6 cubic centimeters per minute) has been investigated in vivo demonstrating that a large and uniform ablation zone may be obtained rapidly. However, no experimental demonstration was provided that such volumetric lesion is indeed centered on a specific predefined target in 3D, i.e. no proof of absence of thermal buildup drift during the sonication. The effective spatial control of the induced thermal lesion during fast volumetric ablation should be considered as a major safety issue. Therefore before clinical trials, it is highly desirable to evaluate in animal models, the accuracy of the spatial control of ablation for a given volumetric HIFU sonication paradigm. We describe here a method to create a user-defined ballistic target as absolute reference marker that is MR-compatible and MR-detectable, while also being a well-established histology staining.