A technique for achieving submillimeter accuracy of volume-staged stereotactic radiosurgery.

A technique for delivering high-precision volume-staged stereotactic radiosurgery has been developed with Leksell Gamma Knife Perfexion for treating large arteriorvenous malformations (AVMs). The technique employs a hybrid method of combining landmark registration and voxel-based 3D image registration to enable multiple staged partial-volume treatments that accommodate repeated stereotactic frame placements. The technique was clinically implemented at our institution and the results were analyzed for a series (n=14) of large AVM cases treated since 2007. Overall, an averaged 0.34±0.09 mm in matching procedural accuracy versus standard single-fraction radiosurgery was found for these treatments. Such a result is a factor of 3-4 times lower than those previously reported, and it approaches the physical accuracy of the latest Leksell Gamma Knife Perfexion system. In conclusion, volume-staged radiosurgery has been demonstrated to be deliverable with the same level of accuracy as standard single-fraction radiosurgery.