Waveguides in medical ultrasonics

Propagation of ultrasound in a number of thin solid elastic waveguides is described from the Pochhammer theory. The waveguides discussed have radii equal to the radii of stylets of the most frequently used biopsy needles. The group velocities of the modes and the form of the particle amplitudes of the lowest longitudinal and flexural modes in each of the styles at a frequency of 3.5 MHz are presented.