Why might exposure be increased when using a grid in digital radiography?

• A. To reduce patient dose.
• B. To improve patient comfort.
• C. To compensate for scatter reduction and maintain receptor exposure.
• D. To accelerate image processing.

Answer: (C)

Grids improve image contrast by absorbing scattered photons that would otherwise reach the detector, but they also attenuate some of the primary beam. To keep the same level of exposure at the image receptor (and therefore the same brightness and diagnostic utility on the digital detector), you need to increase the exposure factors, typically the mA·s (and sometimes adjust technique). In digital radiography, this required increase is described by the grid factor—the higher the grid ratio, the more exposure is needed to compensate for primary-beam attenuation. The result is a higher patient dose, but the image quality benefits from reduced scatter. The other options don’t fit because a grid’s main effect is not to reduce dose, improve comfort, or speed up processing; its primary trade-off is increased exposure to offset scatter reduction.