Prostate cancer affects over 241,740 U.S. males annually, making it the most prevalent cancer type and second leading cause of cancer mortality in men. One frequently utilized method of treating prostate cancer is brachytherapy (BT), or implantation of radioactive seeds into the prostate. The success of brachytherapy chiefly depends on the ability to intra-operatively tailor the radiation dose to the patient's individual anatomy, i.e. adequately cover the prostate with sufficient radiation while simultaneously avoiding excessive radiation to surrounding organs. Many of the challenges that limit brachytherapy can be addressed by incorporating closed-loop feedback in the brachytherapy implant procedure. That is as seeds are implanted into the prostate, their actual positions are measured and fed back to the treatment planning system, which recalculates the dosimetry and re-optimizes the plan. <br/><br/>This proposal leverages prior and ongoing research between the CISST ERC and Acoustic MedSystems to provide an integrated, commercially-viable system with following capabilities: (1) precise intra-operative localization of the implanted radioactive seeds; (2) intra-operative dosimetry and rapid re-optimization of the brachytherapy implant plan; and (3) the ability to accurately and efficiently execute the updated implant plan. <br/><br/>The major goal of the improved process is to minimize human errors with a procedure that has a feedback mechanism for accurate and optimized dosimetry and robotic assistance in the delivery of needles in accordance with a re-optimized implant as the procedure progresses.