Patent ID: 7317786

Claim:
A gating device to delimit an x-ray beam, said gating device comprising: a device housing; first and second absorber elements mounted in said device housing opposite each other; an adjustment device connected to said first and second absorber elements for moving said absorber elements relative to each other to set a spacing between said first and second absorber elements forming a slit for passage of an x-ray beam therethrough; each of said absorber elements having an absorber element edge shaped to give said slit a slit width that varies in a longitudinal direction of the slit, said slit width increasing outwardly, from a central position, toward respectively opposite ends of said slit, each slit edge, in said longitudinal direction of said slit, having a middle region producing a uniform width of said slit, and further regions respectively disposed on opposite sides of said middle region that produce a linearly increasing slit width in said longitudinal direction of said slit; and said adjustment device producing a parallelogram-like relative movement between said absorber elements.