Prostate cancer is one of the most common types of cancer in men. Its diagnosis by biopsy requires a high level of expertise and precision from the surgeon, so the results are highly operator-dependent. The aim of this work is to develop a robotic system for assisted ultrasound (US) examination of the prostate, a prebiopsy step that could reduce the dexterity requirements and enable faster, more accurate and more available prostate biopsy. We developed and validated a laboratory setup with a collaborative robotic arm that can autonomously scan a prostate phantom and attached the phantom to a medical robotic arm that mimics the patient's movements. The scanning robot keeps the relative position of the US probe and the prostate constant, ensuring a consistent and robust approach to reconstructing the prostate. To reconstruct the prostate, each slice is segmented to generate a series of prostate contours converted into a 3D point cloud used for biopsy planning. The average scan time of the prostate was 30 s, and the average 3D reconstruction of the prostate took 3 s. We performed four motion scenarios: the phantom was scanned in a stationary state (S), with horizontal motion (H), with vertical motion (V), and with a combination of the two (C). System validation is performed by registering the prostate point cloud reconstructions acquired during different motions (H, V, C) with those obtained in the stationary state. ICP registration with a threshold of 0.8 mm yields mean 83.2\% fitness and 0.35 mm RMSE for S-H registration, 84.1\% fitness and 0.37 mm RMSE for S-V registration and 79.4\% fitness and 0.37 mm RMSE for S-C registration. Due to the elastic and soft material properties of the prostate phantom, the maximum robot tracking error was 3 mm, which can be sufficient for prostate biopsy according to medical literature. The maximum delay in motion compensation was 0.5 s.

翻译：前列腺癌是男性最常见的癌症类型之一。其活检诊断要求外科医生具备高超的专业技能和精确度，因此结果高度依赖于操作者。本研究旨在开发一种用于辅助前列腺超声检查的机器人系统，该步骤是活检前的关键环节，可降低对操作者灵巧性的要求，并实现更快速、更准确、更普及的前列腺活检。我们开发并验证了一个实验室装置，该装置采用协作机器人臂自主扫描前列腺仿体，并将仿体连接至模拟患者运动的医疗机器人臂。扫描机器人保持超声探头与前列腺的相对位置恒定，确保重建前列腺的方法具有一致性和鲁棒性。为重建前列腺，我们对每个切片进行分割以生成一系列前列腺轮廓，并将其转换为用于活检规划的三维点云。前列腺的平均扫描时间为30秒，平均三维重建时间为3秒。我们实施了四种运动场景：仿体在静止状态下扫描（S）、水平运动下扫描（H）、垂直运动下扫描（V）以及两种运动复合下扫描（C）。系统验证通过将不同运动状态（H、V、C）下获取的前列腺点云重建结果与静止状态下获得的结果进行配准来完成。采用阈值为0.8毫米的ICP配准方法，S-H配准的平均拟合度为83.2%、均方根误差为0.35毫米；S-V配准的平均拟合度为84.1%、均方根误差为0.37毫米；S-C配准的平均拟合度为79.4%、均方根误差为0.37毫米。由于前列腺仿体材料的弹性和柔软特性，机器人最大跟踪误差为3毫米，根据医学文献记载，该精度足以满足前列腺活检需求。运动补偿的最大延迟为0.5秒。