Free placement trans-skull Doppler system with 1.0MHz array ultrasonic probe

This paper describes a trans-skull ultrasonic system that measures the blood flow velocity through the brain´s blood vessel under skull. In this system, we use an ultrasonic array probe with the center frequency of 1.0MHz. The system determines the blood flow by Doppler effect. This Doppler effect is examined by the center of gravity shift in the frequency domain. We test the system in the condition of the water flow in silicon tube under the cow scapula. The experimental result shows that the system detects the flow velocity by Doppler effect and confirms the usefulness of the method under skull.