Radiation Safety: ALARA, Exposure Monitoring, and Dose Levels

Radiation safety programs are essential for protecting people who work with or near sources of ionizing radiation. A strong program is built on three key areas: keeping exposure as low as reasonably achievable (ALARA), monitoring exposure effectively, and understanding dose levels. Together, these principles help safeguard workers, the public, and the environment while ensuring compliance with strict regulations.

Understanding ALARA

What Is ALARA?

ALARA stands for “As Low As Reasonably Achievable.” It means radiation exposure should always be minimized—not just kept under legal limits. Every effort should be made to reduce doses by balancing technical ability, cost, practicality, and safety.

Why ALARA Matters

The principle goes beyond compliance. It is about continuous improvement in safety practices. High doses of radiation can cause immediate health problems, while even low doses may increase long-term risks such as cancer. Following ALARA ensures workplaces remain safe, responsible, and compliant.

How ALARA Is Applied

Radiation workers and safety officers apply ALARA through three main strategies:

• Time – Spend less time near radiation sources.

• Distance – Keep as much space as possible between the person and the source.

• Shielding – Use barriers or protective equipment to block or reduce exposure.

These practices, combined with ongoing monitoring, form the foundation of radiation protection.

Monitoring Radiation Exposure

Types of Exposure

Radiation exposure can occur in different ways:

• External exposure – radiation from a source outside the body.

• Internal exposure – radioactive material enters the body through inhalation, ingestion, or absorption.

• Occupational exposure – workers in medical, research, and industrial facilities face regular risks that require careful oversight.

Methods of Monitoring

Monitoring is the cornerstone of radiation safety. Two main methods are used:

• Personal Monitoring – Workers wear devices such as dosimeters or badges to record individual exposure.

• Area Monitoring – Instruments measure radiation in the workplace environment to identify potential hazards.

Routine monitoring ensures exposure stays within regulatory limits and alerts safety officers to possible problems.

Role of Dosimeters and Badges

Dosimeters and radiation badges provide accurate data on personal exposure, often recorded quarterly. They help radiation safety officers (RSOs) verify compliance, detect unusual exposure trends, and investigate when levels exceed ALARA guidelines.

Exposure Levels in Radiation Safety

Defining Exposure Levels

Radiation dose levels are measured in units such as millirem or millisievert. Regulatory agencies like the NRC set quarterly and annual dose limits, which are built into radiation safety policies.

Investigating Exceedances

If exposure goes above defined thresholds, an ALARA investigation is required. The process usually involves:

• Reviewing work practices and equipment use.

• Checking badge accuracy and proper assignment.

• Identifying whether additional shielding, training, or procedural changes are needed.

ALARA Levels 1 and 2

Most programs use tiered ALARA guidelines:

• Level 1 (10% of the dose limit) – Worker is notified, and safety practices are reviewed.

• Level 2 (30% of the dose limit) – A full investigation is launched, often with the RSO and radiation safety committee.

These levels act as early warning systems to prevent workers from ever approaching regulatory limits.

Training and Responsibilities

Training Staff and Personnel

Training ensures all workers understand radiation safety principles, how to use monitoring devices, and the importance of ALARA. Programs should cover:

• Basics of ionizing radiation.

• How to wear and read dosimeters.

• Proper use of shielding and distance.

• Procedures for reporting unusual exposures.

Responsibilities of Radiation Workers

Radiation workers play a direct role in safety by:

• Wearing monitoring devices at all times.

• Following established work practices.

• Reporting safety concerns to supervisors or the RSO.

• Supporting a culture of continuous improvement in radiation safety.

When everyone takes responsibility, radiation doses remain well below regulatory limits.

Building a Culture of Safety

Radiation safety is not just about following rules—it’s about building a proactive culture of protection. By applying ALARA principles, monitoring exposure effectively, and investigating dose levels, organizations can reduce risks and keep workers safe.

At Global Radiation Physics (GRP), we specialize in radiation protection services that go beyond compliance. From exposure monitoring programs to expert safety training, our team helps organizations build reliable, effective, and compliant safety systems.

Contact Global Radiation Physics today to strengthen your radiation safety program and ensure your team works with confidence and protection.

FAQ

Q1: What does ALARA stand for in radiation safety? 

ALARA means “As Low As Reasonably Achievable,” a principle requiring radiation doses to be minimized whenever practical.

Q2: What are ALARA Level 1 and Level 2? 

Level 1 (10% of dose limit) triggers a review of procedures, while Level 2 (30%) requires a full investigation and corrective actions.

Q3: Why is radiation exposure monitoring important? 

Monitoring ensures that doses remain within regulatory limits, identifies risks early, and helps maintain a safe work environment.

Q4: What devices are used to track exposure? 

Radiation workers use dosimeters and badges, which record individual exposure levels over a set period.