Figure 2 –

Coordinate systems involved in projecting beam voxels into MR image space. Acoustic voxels are defined by the motor stage (M), registered to the tracked position of the hydrophone tip, and converted to transducer coordinates (T). At the scanner these acoustic voxels are projected into MR scan volume (S) after fiducial registration. The reference (R) is used when localizing fiducials in physical space and tracking the transducer.