Abstract
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.
Abstract (translated)
前列腺癌是男性中最常见的癌症类型之一。其通过活检进行诊断，需要外科医生具备高超的技艺和精准度，因此结果很大程度上取决于操作者的技能水平。本研究旨在开发一种用于辅助超声（US）检查前列腺的机器人系统，这是一种在活检前进行的步骤，可以减少灵巧性要求，并使更快、更准确且易于获取的前列腺活检成为可能。 我们设计并验证了一个实验室设置，其中使用了一种协作式机械臂，该机械臂能够自主扫描一个模拟前列腺的模型。此外，还把这个模拟前列腺模型连接到了另一个医疗机器人手臂上，以模仿患者的运动。此系统确保了超声探针和前列腺之间的相对位置不变，从而保证了重建前列腺的一致性和稳定性。 为了重建前列腺，我们对每个切片进行了分割处理，生成了一系列前列腺轮廓，并将其转化为用于活检计划的三维点云数据。平均扫描一个前列腺的时间为30秒，而平均三维重建时间仅为3秒。我们在四种运动场景中进行了实验：模拟静止不动（S）、水平移动（H）、垂直移动（V）以及上述两种组合（C）。为了验证系统性能，我们通过不同运动状态下的点云重建结果与静止状态下获得的数据进行配准注册。 使用ICP（迭代最近点）算法并在阈值0.8毫米的情况下，S-H运动注册的平均一致性率为83.2%，均方根误差(RMSE)为0.35毫米；S-V注册的平均一致性率是84.1%，RMSE为0.37毫米；S-C组合运动注册的一致性率为79.4%，RMSE也为0.37毫米。由于模拟前列腺模型具有弹性软材料特性，机械臂的最大跟踪误差达到了3毫米，这一数值根据医学文献来说仍然足够满足进行前列腺活检的要求。同时，在运动补偿中的最大延迟为0.5秒。 这项研究展示了开发用于辅助超声检查的机器人系统的潜力，该系统能够帮助提高前列腺癌诊断的准确性和可及性，并且在实际应用中具有很高的价值。
URL
https://arxiv.org/abs/2601.05661
