- Patients must have a plan to begin partial brain radiotherapy within 5-9 days after beginning R115777, and within 35 days (5 weeks) of the surgical procedure that established the diagnosis; radiotherapy must be given at the Radiation Oncology Department of the registering ABTC institution; radiotherapy must be given by external beam to a partial brain field in daily fractions of 2.0 Gy, to a planned total dose to the tumor of 60.0 Gy; stereotactic radiosurgery and brachytherapy will not be allowed