Alara

ALARA, an acronym for As Low As Reasonably Achievable, is a core principle of radiation protection. It requires that radiation exposures be kept as low as practicable, taking into account economic and social factors, while ensuring that any residual risk is justified by the benefits of the activity. ALARA is implemented through optimization—continually evaluating practices to reduce dose from all sources without compromising essential tasks.

Originating in the 1950s with the U.S. Atomic Energy Commission and later codified by the International Commission on Radiological Protection, the ALARA principle has become standard in radiation safety across medicine, industry, and research. It guides regulators, employers, and professionals to minimize exposure by design, procedure, and education.

Implementation typically follows a cycle of planning, dose assessment, and controls. Strategies include engineering controls (shielding, containment), administrative controls (procedural changes, scheduling, dose tracking), and personal protective equipment. Practitioners seek to reduce dose toward lower reference levels and use dose estimates to justify each operation.

Applications span diagnostic radiology and interventional procedures, computed tomography, industrial radiography, nuclear power plant operation, and laboratory research. In each case, ALARA requires balancing radiation reduction with the necessity of the procedure, often employing dose limits, reference levels, and justification of the activity.

Limitations and considerations include the subjectivity of what is reasonable, potential conflicts with timely medical or industrial needs, and the need for ongoing commitment and resources. ALARA is distinct from, but complementary to, regulatory dose limits; it is an ongoing optimization process enforced by safety culture and oversight.