Define occupational exposure and its importance in

• Identify situations excluded from occupational exposure
• Understand the role of The Basic Safety Standards (BSS).
• Outline responsibilities of licensees (employers) and workers in radiation
• Recognize worker rights and conditions of
• Understand special considerations for pregnant and young
• Differentiate between controlled and supervised areas and how to establish them.
• Explain methods for controlling access and examples in radiology
• Describe local rules, supervision, and content of local
• Identify types of Personal Protective Equipment (PPE) and their
• Understand individual monitoring: purpose, devices, and
• Recognize workplace monitoring types and survey meter
• Understand investigation levels and incident
• Analyze occupational exposure scenarios and apply safet

Definition:  It is the amount of radiation received by workers during job activities

Why is it important?

• It affects the health and safety of workers in radiation environments.
• Ensures compliance with regulatory dose limits to prevent long-term health risk

13.1: Occupational exposure – Regulatory aspects          

• This definition excludes:
• Natural background radiation
• Medical exposures received as a patient
• Exposures from practices or sources specifically exempted by the Basic Safety Standards (BSS

13.1: Occupational exposure – Regulatory aspects         

• The BSS is a set of international standards developed by the IAEA for radiation
• Purpose:
• Protect people and the environment from the harmful effects of ionizing radiation.
• Provide a framework for the safe use of radiation sources in all practices.

13.1: Occupational exposure – Regulatory aspects                     

• The licensee (typically the employer) holds the primary responsibility for radiation safety.
• Key Obligations:
• Ensure compliance with the
• Establish a radiation protection program.
• Provide necessary resources, training, and
• Limit and optimize work

13.1: Occupational exposure – Regulatory aspects              

• Workers play a vital role in ensuring their own safety and that of
• Responsibilities:
• Follow established safety procedures and local
• Use protective equipment
• Attend required training.
• Report any safety concerns to the RPO

13.1: Occupational exposure – Regulatory aspects                          

• Workers’ rights and conditions related to occupational exposure are
• Key Points:
• No discrimination based on potential for radiation
• No special compensation should be offered as an alternative to proper protection.

Alternative employment should be provided if a worker is deemed unfit to work with radiation

13.1: Occupational exposure – Regulatory aspects                   

• Special considerations apply to protect the

embryo/fetus.

• Notification: Female workers should inform their employer as soon as they are aware of pregnancy.
• Dose Limits: The dose limit to the fetus is the same as for a member of the public (1 mSv per year).
• Work Adjustments: The employer should adapt the working conditions to ensure the dose to the fetus is ALARA.

13.1: Occupational exposure – Regulatory aspects                            10

• Individuals under 16 years old should NOT be occupationally exposed to radiation.
• Persons under 18:
• May work in controlled areas only under direct supervision.
• Work should be limited to training purposes.
• Exposure should be kept ALARA.

13.1: Occupational exposure – Regulatory aspects         

• Why Classify?
• To ensure appropriate protective measures are in
• To control normal exposures and prevent accidental high
• Controlled Area: An area where special procedures and controls are needed due to a potential for significant radiation exposure

13.1: Occupational exposure – Regulatory aspects               

• Factors to Consider:
• Types of radiation sources
• Expected dose rates.
• Likelihood of
• Nature and extent of protective measures needed.

Workload and occupancy factors

13.1: Occupational exposure – Regulatory aspects            

• Access to controlled areas should be restricted.
• Methods:
• Administrative Controls: Work permits, access logs, designated
• Physical Barriers: Doors, locks,
• Warning signs, including the trefoil symbol, should be posted at access points. (Image: Trefoil symbol and warning sign)

13.1: Occupational exposure – Regulatory aspects                   

• X-ray Rooms: Where diagnostic or therapeutic X-ray equipment is
• Fluoroscopy Rooms: Due to the potential for higher doses during real-time imaging.
• Operating Rooms with C-arms: Mobile X-ray units in surgical settings require careful control.
• Nuclear Medicine Departments: Areas where radioactive materials are used for diagnosis and treatment.

13.1: Occupational exposure – Regulatory aspects                    

• Areas where there is a potential for exposure but the risk is lower than in a controlled area.
• Examples:
• Areas adjacent to X-ray
• Areas where mobile X-ray units are
• Waiting areas for patients undergoing nuclear medicine

13.1: Occupational exposure – Regulatory aspects                

• Local Rules: Written procedures specific to the workplace that provide detailed safety instructions.
• Supervision: Trained personnel responsible for overseeing work activities and ensuring compliance with local rule

13.1: Occupational exposure – Regulatory aspects       

• Dosimetry Procedures: How to wear, handle, and store personal
• Radiation Safety Practices: Specific instructions for minimizing exposure during procedures.
• Emergency Procedures: What to do in case of accidents, spills, or equipment malfunctions.

13.1: Occupational exposure – Regulatory aspects          

• Licensees must provide workers with

appropriate PPE to reduce exposure.

• Key PPE Items:
• Lead aprons
• Thyroid shields
• Protective eyewear
• Leaded gloves

13.1: Occupational exposure – Regulatory aspects             

• Made of lead or other high-Z material to attenuate X-
• Minimum Lead Equivalence:
• 25 mm Pb for X-ray equipment operating up to 100 kV.
• 35 mm Pb for equipment operating above 100 kV.
• Apron Styles: Wrap-around, front protection only (when facing the source).

13.1: Occupational exposure – Regulatory aspects

• Higher potential for exposure requires additional protective measures.
• Key Devices:
• Ceiling-suspended lead screens
• Protective lead curtains on the patient table
• Mobile lead shields for the operator

13.1: Occupational exposure – Regulatory aspects                    

• Purpose: To track individual doses and ensure they remain within
• Required For: Workers regularly working in controlled areas or those likely to receive a significant dose.

13.1: Occupational exposure – Regulatory aspects                     

• Radiology Staff: Radiologists, Radiographers, Medical Physicists, Nurses, RPOs
• Other Medical Professionals: (If they frequently work with radiation)
• Cardiologists (during interventional procedures)
• Surgeons (using fluoroscopy in the OR)
• Endoscopists 

13.1: Occupational exposure – Regulatory aspects                       

• Thermoluminescent Dosimeters (TLDs): Crystals that store energy from radiation.
• Optically Stimulated Luminescence Dosimeters (OSLs): Similar to TLDs, but read using light.
• Film Badges: Photographic film that darkens in proportion to radiation exposure.
• Electronic Personal Dosimeters: Provide real-time dose readings and

13.1: Occupational exposure – Regulatory aspects       

• Typically worn at chest level, between the shoulders and
• Under the Apron: For accurate estimation of the effective
• Multiple Dosimeters: May be needed for specific procedures or high-dose areas (e.g., one under the apron, one at the collar).

13.1: Occupational exposure – Regulatory aspects       

• Formula: E = 5 H_w+ 0.025 H_n
• E = Effective dose
• H_w = Dose at waist level (under the apron)
• H_n = Dose at neck level (over the apron)
• Why this Formula? Accounts for the shielding provided by the lead apron and its effect on dose distribution.

13.1: Occupational exposure – Regulatory aspects                

• Monitoring Period: Usually one month, but should not exceed three
• Dosimeter Exchange: Timely exchange is essential to avoid losing dose information.
• Reporting: Dosimetry reports should be provided to the licensee and workers regularly.

13.1: Occupational exposure – Regulatory aspects          

• Contain crystals that store energy when exposed to
• Heating the crystals releases light proportional to the absorbed (Image: TLD reader)
• Advantages: Sensitive, reusable, wide dose

13.1: Occupational exposure – Regulatory aspects                      

• Similar to TLDs but use light to stimulate the release of stored (Image: OSL reader)
• Advantages: Even more sensitive than TLDs, wide dose range, can be re-read.

13.1: Occupational exposure – Regulatory aspects                       

• Contains photographic film and filters.
• Filters help differentiate between types of
• Measures: Beta, gamma, and X- ray radiation.
• Limitations: Less sensitive than TLDs or OSLs.

13.1: Occupational exposure – Regulatory aspects                        

• Provide instant dose
• Features:
• Dose rate display
• Audible and visual alarms
• Data logging capabilities
• Useful for: High-dose rate procedures and real-time

13.1: Occupational exposure – Regulatory aspects                          

• Regular monitoring of the workplace is essential to ensure
• Types of Monitoring:
• Area Surveys: Regular measurements of radiation levels in work
• Leakage Testing: Checking equipment for radiation leakage to ensure it is within allowed limits.
• Environmental Monitoring: Monitoring for contamination in areas where unsealed sources are used

13.1: Occupational exposure – Regulatory aspects                            32

Detector Type:

Choose based on application needs (Geiger-Müller for general use, ionization chambers for high dose rates, scintillation for low-level detection).

Detection Range:

Ensure the meter covers expected radiation levels (µSv/h to Sv/h). Energy Response:

Verify accurate response across the radiation energy spectrum (gamma, X-rays, etc.).

Accuracy:

Aim for accuracy within ±10% of the actual dose rate.

Response Time:

Fast response (a few seconds) is crucial for real-time monitoring.

Calibration:

Regular calibration is needed for reliable readings.

• Pre-defined levels for doses, dose rates, or other parameters that trigger a formal investigation.
• Purpose:
• To identify potential problems or weaknesses in the radiation protection program.
• To ensure that doses are kept

13.1: Occupational exposure – Regulatory aspects                         

• Exposure rate exceeding 25 µSv/h in controlled

• exceeding

(under the apron).

• exceeding 6 mSv (for occupationally exposed workers).

exceeding

reading significantly

on surfaces.

• radiation in a normally low-radiation area.

radiation exposure due to equipment malfunction.

• Radiation levels exceeding

during interventional procedures.

• Formal investigations require a written report documenting the
• Report Content:
• Description of the event
• Cause of the event
• Doses received (if applicable)
• Corrective actions taken
• Recommendations to prevent recurrence

13.1: Occupational exposure – Regulatory aspects                            

• Accurate and complete records are crucial for radiation protection
• Types of Records:
• Exposure Records: Individual dose records for all monitored
• Medical Records: Health surveillance results and any relevant medical
• Workplace Monitoring Data: Results of area surveys, leakage tests,
• Equipment Records: Installation, maintenance, and testing records for radiation equipment.
• Training Records: Documentation of radiation safety training for
• Incident Reports: Records of any incidents or accidents involving
• Scenario: You’re the RPO in a busy operating room. A surgeon is using a mobile C-arm for a lengthy orthopedic procedure. The surgeon insists on staying close to the field for optimal visualization, leading to higher than usual exposure for both the surgeon and the assisting staff.

• Question: How would you address this situation, balancing the surgeon’s needs with radiation safety principles? What practical strategies could you implement to minimize exposure in this scenario?

Discussion Points:

• Importance of communication and collaboration with medical
• Techniques for dose optimization during fluoroscopy (pulsed mode, collimation, less frames,..).
• Use of PPEs (lead drapes, thyroid collars).
• The role of real-time dose monitoring and

Scenario: A radiographer’s personal dosimeter reports an unusually high dose for the month. The individual claims to have followed all safety protocols, and there were no known incidents or equipment malfunctions.

Question: How would you investigate this situation to identify the cause of the elevated dose? What factors would you consider, and what steps would you take to prevent it from happening again?

Discussion Points:

• Importance of a thorough investigation (review of work practices, equipment checks, potential sources of error).
• Recognizing potential for dosimeter reading errors.
• Importance of regular training and reinforcement of safety
• Continuous quality improvement in radiation protection

Scenario: A worker reports losing their personal dosimeter. It is unclear when or where it was lost, and it cannot be located.

Question: How do you determine the potential dose received by the worker in the absence of a dosimeter reading? What actions are necessary, and what are the regulatory implications?

Discussion Points:

• Reconstruction of the worker’s activities and potential exposure (review of work schedules, patient logs, interviews).
• Using workplace monitoring data and dose estimates from similar
• Reporting requirements to regulatory authorities.
• Importance of emphasizing dosimeter security and proper

Scenario: A radiographer who has just declared her pregnancy expresses concerns about continuing to work in the X-ray department, even with proper protection. She is worried about potential risks to the fetus.

Question: How would you address her concerns and counsel her on the risks and safety measures in place? What options are available to ensure her and the fetus’ safety while respecting her work preferences?

Discussion Points:

• Open and honest communication about radiation risks and the effectiveness of protective measures.
• Review of dose limits for pregnant workers and the importance of
• Discussion of potential work adjustments or
• Importance of a supportive work environment and addressing individual concerns.

Scenario: Despite your efforts to promote a strong radiation safety culture, you observe complacency among some staff members. They believe that significant exposures are unlikely in their department and become lax about following safety protocols.

Question: What strategies can be used to overcome this complacency and foster a proactive approach to radiation safety among the team?

Discussion Points:

• Importance of ongoing education and training, emphasizing real-world examples of overexposures.
• Promoting open communication and a “no-blame” culture for incident
• Engaging staff in regular safety reviews and improvements to the radiation protection program.
• Recognizing and rewarding good safety

Question 1: What is the primary definition of occupational exposure?

1. Any radiation received by workers during job
2. Natural background radiation
3. Medical exposures received as a
4. Exposures from practices exempted by Basic Safety

• Question 2: Which international standards set by the IAEA provide a framework for radiation protection?
• NCRP Report 160
• ICRP Publication 103
• The Basic Safety Standards (BSS)
• AAPM Report No. 96

What is a key responsibility of a worker in ensuring radiation

safety?

1. Only following instructions from the Radiation Safety
2. Using protective equipment correctly and attending required
3. Ensuring all radiation safety regulations are met by the
4. Providing compensation for any accidental

• Question 2: Individuals under 16 years old should NOT be occupationally exposed to For persons under 18, work in controlled areas should be:
• Unrestricted, with no supervision.
• Limited to training purposes only, under direct supervision.
• Allowed without any restrictions.
• Permitted only if they volunteer.

Question 5:

from radiation and releases it as light when heated?

1. Optically Stimulated Luminescence Dosimeters (OSLs)
2. Film Badges
3. Electronic Personal Dosimeters
4. Thermoluminescent Dosimeters (TLDs)

• Correct Answers for Lecture 3: Occupational Exposure in Radiology

• Any radiation received by workers during job activities.
• The Basic Safety Standards (BSS)
• Using protective equipment correctly and attending required training.
• Limited to training purposes only, under direct supervision.
• Thermoluminescent Dosimeters (TLDs)

Thank You