What are the three cardinal principles of radiation protection aligned with the ALARA principle?

The correct answer reflects the three cardinal principles of radiation protection, which are time, distance, and shielding. Each of these principles plays a crucial role in minimizing radiation exposure to both patients and healthcare professionals.

Time refers to the duration of exposure to radiation. By reducing the time spent in a radiation field, the dose received can be significantly decreased. This principle underscores the importance of efficient procedures and minimizing unnecessary delays during radiological examinations.

Distance involves increasing the physical space between the radiation source and the individual. The intensity of radiation exposure decreases with distance, following the inverse square law: doubling the distance from a radiation source reduces the exposure to one-quarter of its original value. This principle encourages practitioners to maintain a greater distance from the source of radiation whenever possible.

Shielding employs barriers made from materials that can absorb or block radiation, thus protecting those nearby. Common materials used for shielding are lead and concrete, which are effective in attenuating various types of radiation. This principle is crucial in the design of radiology departments and in the selection of protective gear for healthcare professionals.

Together, these three principles help ensure that exposure to radiation is kept as low as reasonably achievable (ALARA), thus prioritizing the safety of both patients and staff during medical imaging procedures.