Abstract: A radiation anti-scatter device comprising a grid and a grid driver connected to the grid for unidirectionaly moving the grid with a variable grid velocity along a path between a starting and an end position, and a method of providing such grid motion. The variable grid velocity may have a velocity profile V1=k1t for a first period and then V2=k2t−m for a second period, where V1 and V2 are velocity, k1 and k2 are constants, t is time, and m is an exponent having a value greater than 0. The anti-scatter device may be a component of a direct radiographic diagnostic imaging system which includes an image-producing element having an array of radiation detectors aligned in rows, and where the anti-scatter device is a grid having vanes oriented at an angle to the detector rows. Radiation emission may be synchronized with the grid motion to optimize a radiograph for a particular grid, radiation source, or examination procedure.