In this project, we propose to develop and evaluate a novel VCN-based positron emission tomography (PET) imaging agent with the hypothesis that VCN will provide a unique objective noninvasive method to evaluate treatment response. At the completion of this preclinical project, we will be immediately ready to commence a clinical trial in men with metastatic prostate cancer that will have a high impact on patient care by providing new objective imaging-based means for deciphering the effectiveness of various treatments in a personalized patient-specific manner.