Which adjustment is preferred when radiographic grids are used to reduce scatter?

When using radiographic grids to reduce scatter radiation, increasing the milliampere-seconds (mAs) is the preferred adjustment. Grids are designed to absorb scattered photons that do not contribute to the image quality, allowing for a clearer diagnostic image. However, because grids also absorb some of the primary beam photons, it is necessary to increase the mAs to compensate for this absorption.

Increasing the mAs enhances the overall exposure to the detector, which is crucial for maintaining optimal image quality. With a higher mAs, there is an increase in the number of photons that reach the image receptor, thus compensating for the photons lost to the grid absorption and ensuring adequate exposure levels are achieved.

Other adjustments, such as decreasing kVp, could lead to reduced penetration of the primary beam, which may result in insufficient contrast and detail. Using a smaller focal spot primarily affects image sharpness rather than exposure, and increasing the source-to-image distance (SID) could result in a decrease in overall exposure because of the inverse square law, necessitating further adjustments to maintain image quality. Thus, increasing the mAs is the most effective method when using grids.