基于超声与光学耦合定位的骨组织无创实时跟踪方法研究

In orthopedic surgery utilizing image-guided surgery (IGS) technology, real-time tracking of bone tissue is the most pivotal part. Existing tracking method, which is based on fixing an invasive tracker on bone tissue, causes some complications such as additional trauma, stress fractures and loosing. It is contrary to the minimally invasive and precise objective of IGS, and largely limits the clinical application. Aiming to solve this problem, based on the early research achievements of ultrasonic and optical tracking concept by applicant, this research aims to propose a non-invasive tracking method by tracking algorithm analysis and optimal design of tracking device. Through analyzing the data precision from multi-point ultrasound matrix, calibrating the coupling precision, and compensating the position, the surface of bone tissue will be computed in real time. By accelerated iterative registering to the pre-operative virtual bone model, the bone tissue will be tracked non-invasively in realtime. This research will not only provide the basic technical support for the innovative navigation system, but also have an important social significance of improving the surgical safety and promoting the clinical application of IGS.

骨组织术中空间位置的实时跟踪是基于图像引导骨科手术导航技术的首要问题，目前多采用在骨组织上植入侵入性跟踪器来实现，这种方法会引起患者的额外创伤，并在植入部位发生应力性骨折及术中松动问题，违背了手术导航微创、精准的目标，严重限制了该技术的临床应用和推广。本项目拟针对这一瓶颈问题,在申请人前期提出的超声-光学耦合定位概念和相关研究成果的基础上，以提供一种骨组织术中位置的经皮跟踪方法为研究目标，开展无创跟踪算法与跟踪器优化设计研究，通过多点超声矩阵式结构的优化设计、多点超声测距精度分析、声-光耦合精度标定及位置补偿，实时经皮获取骨组织表面术中空间位置信息，将其与术前骨组织虚拟模型经加速迭代求解算法来实时配准，实现无创实时跟踪目的。项目的顺利实施不仅为自主创新的手术导航系统提供关键基础技术支持，也将对提高手术安全性、推广手术导航技术临床应用有着重要的社会意义。

图像引导手术过程中对患者目标组织的实时跟踪是实现图像引导关键，现有侵入性跟踪方法带来的额外创伤问题及体表近似跟踪的精度不足问题，限制了手术导航技术的临床应用。本课题基于超声与光学耦合定位，提出了经皮无创的手术导航跟踪方法，研究了超声与光学耦合标定算法，提出了多楔面N线校准块的标定方法，设计了专用精度标定模块。标定精度分析结果表明，该方法所标定的耦合精度可达1.17mm，满足骨科手术精度要求。同时，课题组利用骨组织术中空间位置变换连续性的特点，优化了迭代最近点法的迭代初始点选择，并基于图形加速卡GPU并行算法，实现了无创跟踪实时配准的最优化解析过程。课题组开展了动物实验和尸体实验来验证无创跟踪方法的精度和实时性，实验结果表明，基于超声和光学耦合的无创跟踪方法可减少骨盆骨折复位手术的手术创伤并提高手术精度，具有重要临床应用价值。