The first test is the dynamic needle insertion. Gelatin (12cm length, 9cm width and 5cm thickness) is utilized as a tissue phantom for in vitro needle steering. The gelatin was mixed with boiling water at a ratio of 1 to 1. A 22Gauge medical needle (0.82mm outer diameter) with 45◦ bevel tip is used for steering test. Functional imaging spin echo-planar imaging (field of view 240mm, echo time 1ms, repetition time 2ms, flip angle 20◦ ) is utilized to monitor the real-time needle motion. This imaging protocol provides approx-imately 2Hz update rates. Needle insertion motion without needle rotation is controlled by closed-loop optical encoder feedback with proportional-integral-derivative controller. Fig. 8 depicts six bevel tip needle insertion snapshots during 3T