Research on Reliability Control Algorithm for Puncture Deflection and Continuous Positioning in Prostate Cancer Interventional Therapy

To address the issues of insertion deflection caused by the inherent properties of standard puncture needles in clinical prostate particle implantation, the overemphasis of existing control algorithms on single puncture positioning performance at the expense of continuous puncture reliability, and the lack of precise support for soft tissue environmental stiffness, this study proposes a reliability control algorithm for puncture deflection and continuous positioning for prostate particle implantation. First, an interaction model between the puncture needle and glandular soft tissue is constructed, the deflection mechanism is analyzed, and the core role of soft tissue stiffness parameters in deflection regulation is clarified. Second, by integrating Hooke’s law with measurements from force and displacement sensors, the least squares method is adopted to achieve online estimation of human prostate soft tissue environmental stiffness, providing real-time stiffness parameters for deflection control. Finally, a closed-loop control model incorporating data acquisition, deviation identification and instruction feedback is constructed, the needle posture is adjusted via spatial transformation of the puncture robotic arm, a particle filter algorithm is adopted to evaluate positioning reliability in real time, and the spatial adjustment of the needle tip is derived to ensure continuous puncture accuracy. Comparative experiments on prostate bionic soft tissues demonstrate that the proposed online stiffness estimation method takes approximately 3 s and can rapidly and synchronously track dynamic stiffness variations during puncture, and that the deflection and continuous puncture control method is effective and reliable, achieving a target positioning overlap rate of 95.6%. This algorithm ensures the therapeutic efficacy of prostate particle implantation and provides a phased theoretical reference for research on precision control systems for puncture robots.