Grid Ratio is defined as

Grid Ratio is defined as

• A. Height of lead strips divided by distance between strips
• B. Distance to which grid lines are focused
• C. Number of lead strips per inch
• D. SID at which grid should be used

Answer: (A)

Grid ratio describes how tall the lead strips are compared to the space between them. It is calculated as the height of the lead strips divided by the distance between strips. This ratio matters because a higher grid ratio (taller strips with less space) more effectively absorbs scatter radiation, which improves image contrast. However, it also means more of the primary beam is absorbed, so the technique must be increased to maintain appropriate exposure. The other statements refer to different grid characteristics: focusing distance relates to where the grid is designed to be used and how the grid lines are aligned at a given SID; the number of lead strips per inch is grid frequency (how many strips in a given inch); and the SID at which the grid should be used is about exposure setup, not the ratio itself.

Grid ratio describes how tall the lead strips are compared to the space between them. It is calculated as the height of the lead strips divided by the distance between strips. This ratio matters because a higher grid ratio (taller strips with less space) more effectively absorbs scatter radiation, which improves image contrast. However, it also means more of the primary beam is absorbed, so the technique must be increased to maintain appropriate exposure.

The other statements refer to different grid characteristics: focusing distance relates to where the grid is designed to be used and how the grid lines are aligned at a given SID; the number of lead strips per inch is grid frequency (how many strips in a given inch); and the SID at which the grid should be used is about exposure setup, not the ratio itself.