Grid focal length of x ray grid

The vertical distance between the x ray grid gate planeand the focus is called gate focal length.

Each x ray grid has its own grating focal length. Photographing at this distance will not cause significant loss of the primary ray. It also gives a range of accommodation of the photographic distance, which decreases with the increase of the grating ratio.
Chest photography and head or lumbar photography can not use the same focal length x ray grid. Because the photographic distance of the chest is 180cm, and the photographic distance between the head and the lumbar vertebrae is 100 to 120cm.

Author：X Ray Grids Maker