Scatter is what flattens a radiograph. As body thickness and kilovoltage rise, more radiation reaching the detector is deflected rather than transmitted. That veil lowers contrast until fine detail disappears. A focused anti-scatter grid intercepts most of it, which is why abdomens, spines and chests are imaged through one, while extremities generally are not. The trade is a higher exposure, since the grid stops some useful radiation along with the scatter.
A 10 to 1 ratio sits at the stronger end of general practice. It removes more scatter than a 6 to 1 or 8 to 1 grid, but it also demands more from the radiographer, because the beam must be centred, square to the grid, and at the right distance. Errors that a lower ratio would forgive show as cut-off along one edge or across the whole field, and the cause is not always obvious at first. Departments moving up from a lower ratio should expect that adjustment, and some retraining.
Two practical points follow for digital rooms. First, the strips fall at about four per millimetre, close to what a 139 micrometre detector can resolve, so a stationary grid may produce moiré patterning unless the lines run across the pixel rows. Second, a grid raises the exposure needed, and the Bucky factor puts a number on that, which is why physics teams want it on record.
Medigear.uk collects the outstanding figures from Blackstone so that a department can judge image quality and dose together rather than separately.