1. Apparatus for measuring the momentum transfer spectrum of elastically scattered X-ray quanta comprising: an anode having a focus extended in Y-direction which emits X-radiation in the X-direction; a primary collimator extending in the Y-direction which allows through only X-radiation aimed at a single isocentre, wherein the isocentre is the originating point of a Cartesian coordinates system; an examination area; a scatter collimator arranged between said examination area and the isocentre and configured to allow through only scattered radiation from an object introduced in said examination area, wherein the radiation is emitted at a fixed angle of scatter (Θ); and a detector, wherein the X-component of a scatter voxel of the object is imaged onto the Z-component of the detector, and the detector is located in the Y-Z plane, distanced from the Z-axis, and developed as a two-dimensional pixellated detector having a plurality of energy-resolving detector elements.