Despite the proven efficacy of radiosurgery for the treatment of brain tumors, limited histological information is available after treatment that might allow a better understanding of the relationship between radiation dose, the volume treated, and the response of the surrounding brain to the delivered radiation. The use of an animal model could provide the opportunity to clarify these relationships and answer several other key questions arising in clinical practice. We show here that treatment of small animals with radiosurgery is feasible using a robotically controlled linear accelerator, which offers the advantages of radiosurgery and preserves the potential for fractionated regimens without rigid immobilization. Specifically, we demonstrate the use of a robotically driven linear accelerator to provide radiosurgical treatment to a rat brain tumor model.