PROJECT SUMMARY/ABSTRACT (EXPERIMENTAL IRRADIATION SHARED RESOURCE) The Experimental Irradiation Shared Resource (EI-SR) provides access to state-of-the-art equipment and expert consultation for Rogel Cancer Center (Rogel) members undertaking radiation therapy studies primarily in mouse and rat models and cell lines. First established in 1991, this SR has been approved and funded continuously by the NCI CCSG since its inception. At the last CCSG renewal, the EI-SR received a merit rating of “Outstanding.” The experience and expertise of the EI-SR Director and Managing Director offer Rogel investigators information on dosage and treatment regimens, particularly in animal studies and with a knowledge of standard clinical radiotherapy, to ensure experimental resources are used in an optimal way. EI-SR services are critical to Rogel members interested in radiation biology and radiation therapy, as well as those for whom radiation serves as a research tool.