An apparatus is provided. The apparatus comprises a vibrator configured to vibrate a needle, an ultrasonic scanhead configured to transmit ultrasonic pulses and to receive return signals, and an ultrasonic system coupled to the ultrasonic scanhead. The ultrasonic system comprises a transmitter and receiver module coupled to the ultrasonic scanhead, a displacement estimation module coupled to the transmitter and receiver module, and a display coupled to the displacement estimation module. The transmitter and receiver module is configured to supply energizing pulses to the ultrasonic scanhead to transmit the ultrasonic pulses and to receive electrical signals produced by the ultrasonic scanhead according to the return signals. The displacement estimation module is configured to calculate motion displacements based on phase differences of the electrical signals. The display is configured to display an image according to the motion displacements.
