1. 3D Ultrasound-Guided Robotic Needle
Steering in Biological Tissue
Robotic needle steering systems have the potential to greatly improve medical
interventions, but they require new methods for medical image guidance. Three-dimensional
(3D) ultrasound is a widely available, low-cost imaging modality that may be
used to provide real-time feedback to needle steering robots. Unfortunately, the poor
visibility of steerable needles in standard grayscale ultrasound makes automatic
segmentation of the needles impractical. A new imaging approach is proposed, in which
high-frequency vibration of a steerable needle makes it visible in ultrasound Doppler
images. Experiments demonstrate that segmentation from this Doppler data is accurate to
within 1 to 2 mm. An image-guided control algorithm that incorporates the segmentation
data as feedback is also described. In experimental tests in ex vivo bovine liver tissue, a
robotic needle steering system implementing this control scheme was able to consistently
steer a needle tip to a simulated target with an average error of 1.57 mm. Implementation of
3D ultrasoundguided needle steering in biological tissue represents a significant step
toward the clinical application of robotic needle steering.