What does ALARA stand for, and which three controls does it emphasize to minimize radiation exposure?

• A. As Low As Reasonably Achievable; time, distance, and shielding to minimize radiation exposure.
• B. As Low As Readily Available; duration, proximity, and shielding
• C. Always Limit As Required; time, distance, and ventilation
• D. As Low As Reasonable, Attainable; time, distance, and ventilation

Answer: (A)

ALARA stands for As Low As Reasonably Achievable. It focuses on three controls to minimize radiation exposure: time, distance, and shielding. Reducing the time spent near the radiation source lowers the total dose since exposure accumulates with duration. Increasing the distance from the source greatly lowers dose due to the inverse-square relationship between distance and intensity. Using shielding — barriers or protective equipment such as lead aprons, shields, or wall barriers — attenuates the radiation that reaches the user. Together, these controls help keep exposure as low as possible while still achieving the required clinical task.