ALARA and AERB

ALARA

As Low As Reasonably Achievable: radiation exposure to patients and staff must be kept as low as possible, considering economic and social factors, while still obtaining the diagnostic benefit.

Inverse square law: $I \propto 1/d^2$.

AERB

Atomic Energy Regulatory Board is the Indian regulatory authority (under the Atomic Energy Act, 1962) for radiation safety.

Role in radiation safety

Body	Role
ALARA	Guiding principle: justification, optimisation, dose limits
AERB	Issues licences and registration for X-ray, CT and nuclear medicine facilities
AERB	Sets safety codes and guides, equipment type approval and QA tests
AERB	Inspects, enforces dose limits (public 1 mSv/yr; radiation workers 20 mSv/yr average over 5 years)
AERB	Requires Radiological Safety Officer (RSO), personal dosimeters (TLD/OSL), safe waste handling

Practical measures

Lead aprons and shields, collimation, filtration, dose monitoring, DRLs (diagnostic reference levels), protective room design.

Exam tip

Explain ALARA through time, distance and shielding and AERB as the licensing and enforcement body.