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An individual X ray image alone fails to provide information about size, position, and shape of the object of interest. A stereoroentgenographic image provides more complete information.Binocular vision with volume perception of sur rounding objects allows human beings to orient freely in the environment. The retina of the eye is able to perceive an object image in two different projections. Each point in the space corresponds to specific physiological parallax in the retina. The human visual analyzer provides auto matic and subconscious analysis of this value to deter mine the shape and position of a visible object.Attempts to decode sophisticated X ray images using stereoscopic vision were made soon after the dis covery of X rays. Russian surgeon N. V. Vikhrev demon strated a stereoscopic apparatus of his construction designed to analyze X ray images in Surgical Society, April 1898.The main feature of stereoscopic imaging is to obtain a pair of photographs from two different viewpoints.Upon superposition of stereoscopic X ray images, cognominal points are shifted in parallel to X ray tube displacement (imaging basis). The larger the objectimaging plane distance, the larger is the shift of the cog nominal points (longitudinal parallax difference).If one stereoscopic image is viewed with the left eye and another stereoscopic image is viewed with the right eye, the viewer is able to see the 3 D image of the object.The origin of the artificial stereoscopic effect is due to different physiological parallaxes of different image points because of shift.Artificial stereoscopic effect can be obtained from plane images observing specific conditions of binocular vision:1) images should be viewed simultaneously and inde pendently with left and right eyes;2) the orientation of the images should provide align ment of initial directions along one line and parallel to eye basis of the viewer;3) the viewing beams should intersect at intersection angle no more than 16°; 4) eye accommodation should be consistent with parallax angles; 5) the difference between the image scales should not exceed 16%;6) the image brightness should be no less than 10 Cd/ m 2 .Winston mirror stereoscopes were predominantly used in roentgenology [5].The optical diagram of the Shtumpf stereoscopic binocular used for viewing stereoscopic pairs of digital X ray images is shown in Fig. 1.Left and right vision channels of the Stumpf stereo scopic binocular contain glass prisms R 1 , R 2 . Screw S pro vides targeting of visual axes of eyes L 1 , L 2 to the points of interest m 1 , m 2 of stereoscopic pair of X ray images P 1 , P 2 . M is the imaginable image of the point of interest observed by the viewer.The stereoscopic X ray viewing method is not wide ly used mainly because of increased radiation load caused by an additional X ray exposure. This is particularly true in film X ray chest survey, where radiation load is 3 5 times larger than in roentgenography. Digital X ray apparatuses, including digital X ray chest survey devices, are characterized by decr...

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