Robotic Needle Insertion With 2D Ultrasound–3D CT Fusion Guidance

Puncture robots pave a new way for stable, accurate and safe percutaneous liver tumor puncture operation. However, affected by respiratory motion, intraoperative accurate location of the tumor and its surrounding anatomical structures remains a difficult problem in existing robot-assisted puncture operations. In this paper, a dual-arm robotic needle insertion system with guidance of intraoperative 2D ultrasound (US) and preoperative 3D computed tomography (CT) fusion is proposed, addressing the shortcomings of existing puncture robots. To deal with the challenge of cross-modal and cross-dimensional registration between 2D US and 3D CT, a decoupled two-stage registration approach combining initial vessel structure-based 3D US – 3D CT registration with intraoperative intensity-based 2D US -3D US registration is proposed. To achieve fast and robust ultrasound probe calibration, a method based on an improved N-wire phantom is proposed. Twenty puncture experiments are performed in different breath-holding positions on a respiratory motion simulation platform, and experimental results show that the mean puncture error is 2.48 mm, which can meet the requirements in a wide of clinical scenarios
Note to Practitioners
—In clinical percutaneous liver tumor puncture operation, due to the lack of real-time and clear image guidance, it is difficult to locate the tumor and its surrounding vital anatomical structures. In addition, the stability and accuracy of manual operation are poor. The development of a puncture robot is an effective solution for these problems. However, existing CT and magnetic resonance imaging (MRI) guided robots do not consider the tumor localization errors caused by inconsistent breath-holding positions between preoperative scan period and intraoperative puncture period, and US guided robots are limited by the poor image quality and the narrow field of vision. In this paper, a dual-arm robotic needle insertion system with guidance of intraoperative 2D US and preoperative 3D CT fusion is proposed. This system can take advantage of the real-time ultrasound and clear CT images at the same time, and can provide real-time, clear and all-round guidance for percutaneous liver tumor puncture operation, which has obvious advantages over the existing puncture robots. Phantom experiments have been completed and animal experiments will be carried out in the future.