When a grid is used, what adjustment is typically needed to maintain receptor exposure?

• A. Decrease exposure to compensate
• B. Maintain the same exposure
• C. Increase exposure to compensate
• D. Switch to a non-grid technique

Answer: (C)

Grid systems reduce scattered radiation, but they also absorb some of the primary x-ray beam. That attenuation lowers the amount of radiation reaching the image receptor, so to keep the same receptor exposure you need to increase the exposure factors—typically by raising mAs (and sometimes adjusting kVp slightly depending on the situation). The exact amount depends on the grid’s ratio and frequency, but the principle is to compensate for grid attenuation with higher exposure. Decreasing exposure or leaving it the same would produce an underexposed image, and switching to a non-grid technique would defeat the purpose of using a grid.