Investigation on virtual palpation system using ultrasonic elasticity imaging

In the field of medical ultrasound, ultrasonic elasticity imaging has been developed and used in practical diagnosis. However, unfortunately, elasticity information is now displayed on ordinary 2D screen (for example, CRT). Since elasticity information is haptic information, not visible information, the information is expected to be displayed in "the sense of haptic". In this research, it is attempted that elasticity information is displayed on haptic display for virtual palpation system. In this system, a surface of diseased part is expressed by one rigid plane which has elasticity information. The elasticity information is a function of 2D coordinates of a haptic device on the plane. 3D elasticity information of the diseased part which is measured by ultrasonic elasticity imaging equipment is rendered to the plane by a way which is similar to volume rendering technique, to reduce computational cost and to realize human haptic sense easily in virtual palpation in real time. It is also important to reproduce the haptic sense in the case where a physician slides fingers on the surface in real palpation. The proposed system enables to reproduce the haptic sense in not only the perpendicular direction to the surface but the direction of horizontal movement of fingers on the surface. This system can realize virtual palpation system.