Two of the megavoltage therapy bunkers with their control rooms and adjacent facilities have been upgraded to accommodate Varian HE linear accelerators. As part of the upgrade the rooms were fully refurbished including reconfiguration of mass concrete and steel plate radiation shielding, modifications to the concrete pits and trenches to support differing base frames and servicing, new acoustically treated electrical modulator rooms, removal of neutron doors and rearrangement of chiller plant.