Abstract
We developed a new probe to examine the anisotropy of dermis tissue by ultrasonic velocity measurement and confirmed the reliability of the method. Skin has the characteristic of anisotropy caused by collagen fiber in the dermis tissue. Though the characteristics are thought to be useful for the diagnosis of skin disease, the examination of anisotropy is very difficult and no optimum method has been devised. The characteristics of anisotropy correspond to the arrangement of collagen fiber and the direction of maximum sound velocity is the same as that of fiber. But determining the maximum sound velocity direction is very difficult in a thin skin layer. We applied a couple of wedges conventionally used in the field of acoustic emission to the measurement of sound velocity in skin and designed a sound path in a skin layer with a small load. By examining a skin model made of gelatin, we confirmed the sound propagation path we had expected. We then measured the sound velocity of skin as a function of direction in a human forearm and estimated the fibrous direction.
