ProBot: Robot-Ultrasound Probe for Transrectal and Transperineal Prostate Biopsy

OBJECTIVE: Over the past decade the incidence of prostate cancer (PCa) has been on a steady increase. Efforts to improve PCa outcome include targeted biopsy with magnetic resonance imaging (MRI) and precision sampling. Several biopsy devices are currently available to guide the biopsy with MRI-ultrasound fusion. They commonly use generic handheld ultrasound probes retrofitted for fusion biopsy. Robotic probe manipulation has the potential to reduce the required training, skills, and outcome variability among urologists. Rather than retrofitting an ultrasound probe, we developed a novel cohesive ultrasound-robotic probe (ProBot) that enables a novel needle insertion path. METHODS: Tissue-probe contact frequently deforms the prostate contributing to fusion errors. To minimize deformations, ProBot uses a side-fire probe and its only motion is a robotic rotation about its axis, which can't force the gland. An additional robotic angulation of the needle allows targeting any gland location. As such, only 2 degrees-of-freedom are required for prostate biopsy. However, the probe and robot must allow clearance to angle the needle, thus a special probe and Remote-Center-of-Motion (RCM) robot kinematics were developed. We present their design, ProBot prototype, and adapters for transrectal and transperineal needle access. RESULTS: Pre-clinical tests showed sub-millimeter targeting errors and validated the sterilization process. With IRB approval, transrectal prostate biopsy was successfully performed in two patients. CONCLUSION: ProBot is a novel device for prostate biopsy (robotic, simple, compact, precise) with a successful pilot clinical evaluation. SIGNIFICANCE: A precision, skill independent biopsy device can impact the management of PCa. Additional trials are required.