Study About Non-Contact Measurement of the Speed of Sound in a Parallel-Sides Tissue Using Pass-Through Airborne Ultrasound

Measurement of ultrasonic propagation characteristics in cancellous bone is one of the diagnosis methods of osteoporosis. In the examination, ultrasonic transducers are typically brought into contact with heel sides through an ultrasonic gel to effectively propagate ultrasound. Non-contact measurement of the speed of sound (SOS) in a heel using airborne ultrasound which passed through the heel has been proposed to enable the easy-repeatable and low-cost examination. However, the accuracy of the proposed method hasn't been sufficient in the measurement of agar phantoms or actual heels. The SOS is estimated based on determination of the time of flight (TOF) and measurement of the propagation path of ultrasound. Therefore, TOF determination and path-length measurement in the proposed method are improved. Then, SOS measurement for the parallel-sides agar phantom is evaluated.