Development of instruments to assist accurate puncture of liver tumors for MRI-guided microwave ablation

In MR-guided microwave ablation of liver tumors, real-time MR images including the needle path and the target tumors were essential for accurate puncture. An optical tracking system, integrated in the MR system, played a very important role for the interactive scan plane control. The optical tracking system, however, had some limitations caused by the line of sight between the LEDs and detectors. In addition, the LEDs were slightly ferromagnetic. To solve the problems of this tracking system, we prepared various adaptors for the hand piece. Then, we procured less magnetic LEDs with compatible performance and created new original hand pieces. A hybrid tracking system with optical and electromagnetic detections was also constructed and seamless navigation was enabled. Finally, an MR-compatible motorized robot was developed to chase the preset target point automatically. With these devices to track the target, more convenient and accurate puncture of liver tumor was realized under MR image guidance.