A Tubular Dual-Roller Bending Mechanism Toward Robotic Transurethral Prostate Biopsy

Prostate biopsy procedures as a gold standard for early screening of prostate cancer often suffer from multipass needle perforations to irrelevant perineal tissue, high complication risk, and time consumption. To address these challenges, this article proposes a transurethral prostate biopsy robot that can deliver a flexible biopsy needle inside the prostate from different angles and thus obtain tissue samples from multiple locations. Emphasis is on the design and validation of the transurethral prostate biopsy robot with a detailed introduction of the working principle, mechanism modeling, and function testing. Phantom experiments in kiwi fruit puncture experiments and prostate phantom puncture experiments have demonstrated their potential in clinical application. The transurethral biopsy robot features a 7-mm tubular dual-roller bending mechanism together with a compact driver mechanism. The flexible biopsy needle can bend from 16.0$^\circ$ to 55.8$^\circ$ with a translational stroke of 32.5 mm and an overall rotational stroke of 360$^\circ$, which enable coverage a volume of 142.2 mL, more extensive than that of an enlarged prostate. The average angle positioning and overall positioning error are 0.82$^{\circ }$ and 1.2 mm, respectively. It can provide a minimum of 6.3-N puncture force. The proposed transurethral prostate biopsy procedure is a unique inside-out robotic prostate biopsy method, contributing to a safer and less invasive prostate biopsy procedure.