Ultrasonic endoscope apparatus

摘要

In an ultrasonic endscope apparatus for observing an optical image of a cavity of a body under inspection by forming the optical image with the aid of an objective lens arranged in a distal end of an insertion section of an endoscope and by transmitting the optical image by means of an image guide and for observing an ultrasonic sectional image by arranging an ultrasonic vibrating element in the distal end of the insertion section, a distance between the objective lens and the cavity is measured by detecting a first echo reflected by the cavity, image data representing a locus of a section line of the ultrasonic sectional image is derived in accordance with the measured distance, the image of the section line is displayed on a display device, and the displayed image of the section line is monitored in the superimposed manner with the optical image of the cavity.