Design of a Percutaneous MRI-Guided Needle Robot With Soft Fluid-Driven Actuator

Percutaneous ablation is a standard therapy for most cases of hepatocellular carcinoma (HCC), which is a general type of primary liver cancer. Magnetic resonance imaging (MRI) offers high-contrast images of soft tissue to monitor the ablation procedure. However, the success of MRI-guided ablation still depends on precise intra-tumor probe placement and skin insertion positioning, both of which require highly experienced operators, and can induce inter-operator variability in ablation results. In this letter, we present a semi-automated robotic system for MRI-guided percutaneous needle procedures. The compact and lightweight design enables the direct fixture of robot on the patient body and simultaneous needle targeting at multiple locations with several robots. Accurate (0.89 ± 0.31 mm) needle navigation is achieved by incorporating soft fluid-driven actuators with feedback control and stiffness modulation capabilities. The 3D location of the needle guide is reconfirmed by wireless MR tracking coils. The performance of the robotic platform, such as stiffness, needle positioning accuracy and frequency response was experimentally evaluated. Negligible interference to MR imaging was also validated by an MR compatibility test.