Which unit is used to express exposure rate in radiography?

Which unit is used to express exposure rate in radiography?

• A. R/min
• B. mR/min
• C. Gy/min
• D. Sv/min

Answer: (A)

Exposure rate refers to how much ionization the x-ray beam produces in air per unit time. The standard unit for that in radiography is the Roentgen per minute (R/min), since the Roentgen measures exposure in air and a per-minute rate conveys how rapidly that exposure occurs. Milliroentgen per minute (mR/min) is simply a smaller unit of the same quantity, often used for finer measurements, but the traditional exam wording points to R/min as the primary unit. Units like Gy/min or Sv/min represent dose or dose-equivalent rates in tissue, not exposure in air, so they aren’t used to express exposure rate in this context.

Exposure rate refers to how much ionization the x-ray beam produces in air per unit time. The standard unit for that in radiography is the Roentgen per minute (R/min), since the Roentgen measures exposure in air and a per-minute rate conveys how rapidly that exposure occurs. Milliroentgen per minute (mR/min) is simply a smaller unit of the same quantity, often used for finer measurements, but the traditional exam wording points to R/min as the primary unit. Units like Gy/min or Sv/min represent dose or dose-equivalent rates in tissue, not exposure in air, so they aren’t used to express exposure rate in this context.