Figure 1.

Representative resection cavity (A) as outlined on the day of stereotactic radiosurgery (yellow) with isodose lines from 100% (red) to 50% (blue); (B) contour of a resection cavity recurrence with centroid (pink with red point marker) and serial 1 mm isotropic expansions of the resection cavity (blue, green, orange) created from the day of stereotactic radiosurgery contour (yellow). This was classified as a marginal recurrence because it fell in the zone receiving between 50% and 100% of the prescription dose, with the centroid 3 mm from the edge of the resection cavity.