ABSTRACT

Patients randomized to the SRS arm must undergo volumetric MRI of brain within 7 days of SRS, and the radiation procedure must be delivered within 3-30 days of surgical resection. e SRS treatment is frame based and may be delivered using either the Gamma Knife (GK) Perfexion unit (Elekta, Stockholm, Sweden) or a linear accelerator (LINAC) with arcs or mini-multileaf collimation. Real-time treatment planning is employed. e target is de‚ned as the surgical cavity plus 1 mm margin, and the single-fraction dose to be delivered is de‚ned based on the target volume: 16 Gy for 0-10 cubic centimeters (cc), 14 Gy for 10.1-15 cc, and 12 Gy for >15 cc. e maximum point dose to the optic apparatus is limited to <9 Gy, and 1.0 cc of brainstem may receive 12 Gy.