Abstract: An X-ray inspection system comprises an X-ray source (1) disposed to irradiate an object to be inspected (4) with a beam of X-rays in the form of a fan project from the source (1) through the object (4), detection means (6) capable of discriminating between the intensitities of X-rays coherently scattered through the object (4) at different angles to produce an output signal dependent on the intensity of the X-rays scattered through each of those angles and analyzing means (not shown) operably connected to the detention means (6) to process the output signal to determine the presence of X-rays coherently scattered through one or more pre-determined angles. Collimination means (23) is provided between the detection means (6) and the object (4) and is adapted to pass only X-rays coherently scattered at the different angles from a limited voxel (volume element) depth central at point P. Movement at the collimator (23) along the direction of the beam together with translation of the object by e.g.