Technical note: a comparison of antiscatter grids for digital radiography.

The use of digital radiography (DR) systems offers a number of advantages over film-screen detectors. One potential disadvantage, however, is that some fixed DR systems do not allow the user to change the antiscatter grid to suit the imaging task. Instead, the user must choose the grid at the time of purchase. Six grids, which are offered as installation options for one commercial fixed-room DR system, were experimentally evaluated, using a range of scatter conditions and tube voltages. In addition, three grids, which are available with a portable DR system in which the user can change the grid to suit the imaging task, were also evaluated. The grids were compared using the primary transmission, scatter fraction, and calculated signal-to-noise improvement factor (SIF). It was found that the grids with low atomic number interspace and cover material had an SIF up to 15% higher than did the grids with aluminium interspace and cover material; the grid with a grid ratio of 12:1 had the highest SIF for all tube voltages and scatter conditions tested here. This 12:1 grid probably represents a good general-purpose non-removable grid in DR.