Positioning error evaluation of GPU-based 3D ultrasound surgical navigation system for moving targets by using optical tracking system

Abstract

A near real-time three-dimensional (3D) ultrasound navigation system has been developed for guiding surgery involving internal organs that move and change shape (e.g., abdominal surgery, fetal surgery). In practical applications, significant errors arise between the actual navigation-image positions depending on the time delay of the system. Therefore, the positioning error of the system relative to the target velocity was evaluated. We developed a method for evaluating the positioning error of a graphics processing unit-based 3D ultrasound surgical navigation system (with an optical tracking system) for moving targets. The effectiveness of this system was quantitatively evaluated in terms of its image processing runtime, target registration error (TRE), and positioning error for a moving target. The positioning error was evaluated for a phantom (with an optical tracking marker) moving at speeds of 5-25mm/s, and the navigation target was the center point of the phantom. The imaging range of the volume data was set to the maximum angle and range of the ultrasound diagnostic system (update rate: 4Hz). The image processing runtime was 27.43 ± 4.80ms, and the TRE was 1.50 ± 0.28mm. The positioning error was 4.24 ± 0.12mm for a target moving at a speed of 10mm/s and 5.36 ± 0.10mm for one moving at 15mm/s. The effectiveness of an ultrasound navigation system was quantitatively evaluated by using the positioning error for a moving target. This navigation system demonstrated high calculation speed and positioning accuracy for a moving target. Therefore, it is suitable to guide the surgery of abdominal internal organs (e.g., in fetal and abdominal surgeries) that move or change shape during breathing and surgical approaches.