The primary objective of this SBIR project is to develop a 3-D computer- aided prostate biopsy system to provide physician the guidance in performing real clinical biopsy procedures for individual patient.  The proposed system provides several useful capabilities, including (l) A 3-D master model of the prostate, consisting of a graphical model showing major anatomical structures and a statistical volume showing the probability maps of prostate cancer, will be used to select optimal biopsy sites in model-based biopsy guidance; (2) This 3-D master model will be overlaid onto transrecrtal ultrasound image space, through a blended deformable registration procedure, so that the standard protocol and/or the planned biopsies can be realized with a model-based and image- guided fashion; (3) The system will record the result of biopsies in 3-D so that the follow-on call-back re-biopsies can be better defined and a more accurate algorithm may be derived to estimate tumor volume and other staging parameters.  This novel approach will improve the existing clinical biopsy practice, through on-line multimodal visualization and deformable probability mapping of the biopsy procedure, thus allowing more accurate realization of planned biopsies and more representative samplings of the cancer.  Consequently, this innovation could substantially improve the accuracy of prostate cancer diagnosis and clinical staging, thus improving treatment planning.  The system will also be used as a training module for simulation and/or education purposes.  PROPOSED COMMERCIAL APPLICATIONS: To the best of our knowledge, there has been no previous effort in developing and commercializing a 3-D computer-aided prostate biopsy system for guidance, documentation and training.  Clearly, market demand exists for advanced products that can provide physicians better guidance and documentation in performing prostate needle biopsy with optimized biopsy site and electronic record for follow-on studies and/or re- biopsies.  This SBIR would lead to a 3-D computer-aided prostate biopsy system for hospital use to guide, document and train transrectal ultrasound-guided prostate needle biopsies.  With over 40,000 predicted deaths from prostate cancer every year, the impact of the proposed R&D to healthcare is enormous.