The three basic radiation safety principles to achieve ALARA are:

The three basic radiation safety principles to achieve ALARA are:

• A. Time, Shielding, Containment
• B. Time, Distance, Shielding
• C. Distance, Shielding, PPE
• D. Time, Distance, Ventilation

Answer: (B)

ALARA relies on three ways to cut radiation dose: reducing how long you are near the source, increasing your distance from it, and adding shielding between you and the source. Limiting time directly lowers the amount of exposure you accumulate because the dose is proportional to how long you’re exposed. If you can work faster or take breaks, you reduce the total dose you receive. Distance matters a lot because radiation intensity drops rapidly as you move away. The farther you are, the smaller the dose at your body. In practice, stepping back or staying out of the high-activity area when you’re not actively working dramatically lowers exposure. Shielding provides a barrier that attenuates or blocks radiation. The right material and thickness reduce the radiation reaching you, especially for high-energy sources. Proper shielding is chosen based on the type and energy of the radiation and the work being performed. These three controls—time, distance, and shielding—form the fundamental approach to minimizing exposure. PPE and ventilation or containment can contribute to safety, but they are not the three primary ALARA controls.

ALARA relies on three ways to cut radiation dose: reducing how long you are near the source, increasing your distance from it, and adding shielding between you and the source.

Limiting time directly lowers the amount of exposure you accumulate because the dose is proportional to how long you’re exposed. If you can work faster or take breaks, you reduce the total dose you receive.

Distance matters a lot because radiation intensity drops rapidly as you move away. The farther you are, the smaller the dose at your body. In practice, stepping back or staying out of the high-activity area when you’re not actively working dramatically lowers exposure.

Shielding provides a barrier that attenuates or blocks radiation. The right material and thickness reduce the radiation reaching you, especially for high-energy sources. Proper shielding is chosen based on the type and energy of the radiation and the work being performed.

These three controls—time, distance, and shielding—form the fundamental approach to minimizing exposure. PPE and ventilation or containment can contribute to safety, but they are not the three primary ALARA controls.