ABSTRACT We propose to test the validity and specificity of our targeted ultrasound imaging probes in detecting early stage ovarian cancer (OVCA) by transvaginal ultrasound imaging (TVUS). We then test the predictive validity of these probes in a longitudinal study using the laying hen ? the only widely available animal model of spontaneous OVCA. OVCA is a fatal gynecological malignancy of women. An effective early detection test could reduce high mortality rate due to OVCA and morbidity associated with exploratory surgeries significantly. Serum levels of CA-125, traditional TVUS and their combination failed to improve early detection of OVCA. CA-125 is non-specific and there is no imaging target in the ovary corresponding to elevated serum CA-125 levels. A fresh approach is needed. An efficient targeted imaging strategy requires appropriate targets and suitable imaging modalities/platforms. Our imaging agents, for the first time, will detect the ovarian tumor and tumor associated neo-angiogenic (TAN) microvessels. Ultrasound is currently used for evaluation of genitourinary masses, and introduction of molecular imaging agents for early OVCA detection would enable physicians to use existing TVUS equipment. We developed TVUS imaging probes targeting follicle stimulating hormone receptor (FSHR) expressing ovarian TAN microvessels and glucose regulatory protein 78 (GRP78)- expressing ovarian tumor epithelium. We tested these probes in laying hens. Our preliminary data supports the validity and specificity of these probes for detecting early OVCA using TVUS in association with serum markers providing proof-of-principle. Thus, in Aim 1 we are proposing to develop novel targeted ultrasound imaging agents including FSHR- and GRP78-targeted imaging probes. Aim 2 will establish the targeted imaging intensities for the detection of early stage OVCA. Aim 3 will test the ability of these probes to detect early stage OVCA and establish the false positive rate in the hen model. Because of the difficulty of identifying patients at early stage OVCA and accessing their tissues, we will use the laying hen to accomplish our research goals. Since the team includes clinicians, our intent is to develop these probes for human use, which could be immediately translated into the clinic.