What is the primary purpose of using a grid in radiography?

What is the primary purpose of using a grid in radiography?

• A. Increases contrast by absorption of scatter exiting the patient
• B. Reduces density
• C. Must use more mAs with a grid
• D. Grid use is independent of part thickness

Answer: (A)

Grids are used to control scatter and improve image contrast. Scatter produced inside the patient travels to the detector and creates a fog that lowers detail visibility. The grid sits between the patient and the image receptor and absorbs much of this scattered radiation while letting the primary beam through. This selective absorption increases the difference in brightness between structures on the image, i.e., the image contrast. Because the grid also attenuates some of the primary photons, technique often needs to be increased to maintain receptor exposure. The grid’s primary role isn’t to reduce density or to be independent of part thickness; thicker parts generate more scatter, making the grid more beneficial, and technique must be adjusted accordingly.

Grids are used to control scatter and improve image contrast. Scatter produced inside the patient travels to the detector and creates a fog that lowers detail visibility. The grid sits between the patient and the image receptor and absorbs much of this scattered radiation while letting the primary beam through. This selective absorption increases the difference in brightness between structures on the image, i.e., the image contrast. Because the grid also attenuates some of the primary photons, technique often needs to be increased to maintain receptor exposure. The grid’s primary role isn’t to reduce density or to be independent of part thickness; thicker parts generate more scatter, making the grid more beneficial, and technique must be adjusted accordingly.