IMAGING AND RESPONSE ASSESSMENT CORE (IRAC) SHARED RESOURCE: PROJECT SUMMARY The Imaging and Response Assessment Core (IRAC) is a shared resource (SR) operated by the Department of Radiology within the Washington University School of Medicine (WUSM). The IRAC facilitates research by providing support services and analysis for both standard and novel imaging methods used for characterizing tumor biology and predicting and monitoring response to therapy in patients enrolled in clinical trials performed at the Siteman Cancer Center (SCC). To accomplish this, the IRAC provides a variety of services to investigators including: 1) assistance with protocol development; 2) imaging-related regulatory services; 3) site qualification; 4) coordination of imaging examinations to ensure protocol compliance; 5) data transfer to trial sponsors or external core laboratories; and 6) tumor measurements on both anatomical and functional imaging studies performed by dedicated radiologists and nuclear medicine physicians. Additionally, the IRAC implements new software tools to improve the accuracy and reproducibility of tumor measurements and to allow for incorporation of newer approaches of tumor measurement (for example, three-dimensional volumetric measurements and metabolic tumor volume) into clinical trials at SCC. The overall goal of IRAC is to increase the impact that quantitative imaging plays in clinical cancer research. The IRAC provides unique imaging management and analysis services that are not available elsewhere within the WUSM. The SCC has a large portfolio of clinical trials that use computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET), and the IRAC contributes to the overall success of SCC trials by providing these imaging support services to investigators.