Which statement is true regarding grid ratios and image contrast?

Which statement is true regarding grid ratios and image contrast?

• A. Higher grid ratio decreases image contrast
• B. Grid ratio has no effect on image contrast
• C. Higher grid ratio increases image contrast
• D. Grid ratio only affects dose

Answer: (C)

Grid ratio and image contrast are linked through the way grids handle scattered radiation. In radiography, scattered photons that reach the detector blur detail and lower contrast. A grid sits between the patient and the image receptor and absorbs much of this scatter while mostly transmitting the primary beam. The grid ratio is the height of the lead strips divided by the width of the interspaces. When you increase this ratio, the grid becomes better at blocking scatter relative to the primary beam, so less scattered fog reaches the receptor and the image appears crisper with higher contrast. The trade-off is that more of the primary beam is attenuated by the grid, so you usually need a higher exposure (technique) to maintain receptor exposure, which can raise the patient dose. So, higher grid ratio increases image contrast, which is why that statement is true.

Grid ratio and image contrast are linked through the way grids handle scattered radiation. In radiography, scattered photons that reach the detector blur detail and lower contrast. A grid sits between the patient and the image receptor and absorbs much of this scatter while mostly transmitting the primary beam.

The grid ratio is the height of the lead strips divided by the width of the interspaces. When you increase this ratio, the grid becomes better at blocking scatter relative to the primary beam, so less scattered fog reaches the receptor and the image appears crisper with higher contrast. The trade-off is that more of the primary beam is attenuated by the grid, so you usually need a higher exposure (technique) to maintain receptor exposure, which can raise the patient dose.

So, higher grid ratio increases image contrast, which is why that statement is true.