Which of the following are the three fundamental protective strategies of ALARA?

• A. Reduce time of exposure, increase distance from the source, and employ shielding.
• B. Reduce time of exposure, decrease distance, and remove shielding.
• C. Increase time of exposure, increase distance, and use placebo shielding.
• D. Reduce shielding thickness while increasing distance.

Answer: (A)

ALARA aims to keep radiation doses as low as reasonably achievable by using three practical controls: minimize time spent near the source, maximize the distance from the source, and place appropriate shielding between you and the source. Reducing the time of exposure lowers the total dose in proportion to how long you’re exposed. Increasing distance from the source reduces dose rapidly due to the inverse square relationship—the farther you are, the much lower the dose. Shielding attenuates or blocks radiation, with effectiveness depending on the material and thickness used between you and the source. The option that lists reducing time, increasing distance, and employing shielding aligns with these protective measures. Choices that push for longer exposure, moving closer, removing shielding, or nonsensical shielding do not fit ALARA principles.