In radiography, how does use of a grid affect patient dose, and what is the reason?

In radiography, how does use of a grid affect patient dose, and what is the reason?

• A. It increases patient dose due to the need to penetrate the grid
• B. It reduces patient dose
• C. No effect on dose
• D. It improves image resolution with no dose change

Answer: (A)

Using a grid improves image contrast by absorbing scattered radiation before it reaches the image receptor, but it also attenuates some of the primary beam. To keep the same receptor exposure and image brightness, you must increase the exposure (mAs) to compensate for the grid’s attenuation. This increase in exposure raises the dose delivered to the patient. The grid factor (which depends on grid ratio and frequency) quantifies how much exposure must be raised. So, the reason the dose goes up is the need to penetrate and compensate for the grid’s attenuation while preserving image quality.

Using a grid improves image contrast by absorbing scattered radiation before it reaches the image receptor, but it also attenuates some of the primary beam. To keep the same receptor exposure and image brightness, you must increase the exposure (mAs) to compensate for the grid’s attenuation. This increase in exposure raises the dose delivered to the patient. The grid factor (which depends on grid ratio and frequency) quantifies how much exposure must be raised. So, the reason the dose goes up is the need to penetrate and compensate for the grid’s attenuation while preserving image quality.