Personal Protective Equipment in Radiology

• Issued: November 2013
• Content last reviewed: November 2013

Radiation protection comprises a hierarchy of control measures. Engineered design and construction, administrative policy/procedures and personal protective equipment address the three fundamental principles of dose reduction: time, distance and shielding. In open beam x-ray applications where an x-ray worker must remain in the x-ray room, personal protective equipment (PPE) is the last layer of defence in reducing exposure to ionizing radiation after optimizing all other engineering and administrative controls.

Examples of statutory and regulatory requirements in respect of PPE

Under the Ontario Occupational Health and Safety Act (OHSA), the employer, supervisor and worker have duties with regard to protective equipment (or devices). They include:

• Employer – ensure that protective devices are maintained in good condition; ensure that prescribed protective devices are provided; and ensure that equipment and protective devices are used as prescribed
• Supervisor – ensure that the worker uses or wears the protective devices required by the employer, and works in a safe manner and with the protective devices and measures and procedures required by the Act and the regulations
• Worker – use or wear the protective devices that the worker’s employer requires, and report any defect to his or her employer or supervisor

The intent of PPE is to ensure that the dose equivalent received by a worker is as low as reasonably achievable and that the limits in the Regulation respecting X-Ray Safety (Reg. 861) are not exceeded.

The Regulation respecting X-ray Safety (Reg. 861) made under the OHSA requires protective aprons and gloves, providing shielding equivalent to at least 0.5 mm of lead to be available for persons providing restraint or support to an animal in veterinary x-ray applications.

Workplaces covered by the Health Care and Residential Facilities Regulation (O. Reg. 67/93) are required to develop, establish and put into place written measures and procedures which may deal with but are not limited to: safe work practices, the proper use, maintenance and operation of equipment; and the use and wearing and care of PPE and its limitations, in consultation with the joint health and safety committee (JHSC) or health and safety representative (HSR) (if any). Employers are required to review and revise these measures and procedures at least once a year in light of current knowledge and practice. The employer is also required, in consultation with the JHSC or HSR (if any), to develop, establish and provide worker training and educational programs on relevant OHS measures and procedures.

In settings where workers are required either by O. Reg. 67/93 or their employer to use PPE:

• employers must ensure workers are instructed and trained in the care, use and limitations of PPE before wearing or using it the first time and at regular intervals thereafter
• workers are required to participate in instruction and training
• the PPE provided, worn or used must be properly fitted.

Section 15 of O. Reg. 67/93 requires that a worker who supports, positions or restrains a patient or resident in a health care facility during an x-ray examination be provided with, and wear, a protective apron, gloves and collar (where applicable) having a lead equivalence of at least 0.5 mm.

Workplaces covered by the Regulation for Industrial Establishments (Regulation 851) that require PPE to protect workers from exposure to x-rays must comply with section 79 of Regulation 851 which states:

• A worker required to wear or use any protective clothing, equipment or device shall be instructed and trained in its care and use before wearing or using the protective clothing, equipment or device.
• For workplaces where no sector specific regulation applies, the employer should take every precaution reasonable for the protection of workers to protect them from the hazard of radiation; one method of protecting workers is to ensure appropriate PPE is worn.
• Regulation 543 (X-Ray Safety Code) made under the Ministry of Health and Long-Term Care’s Healing Arts Radiation Protection Act requires that protective accessories of at least 0.5 millimetres (mm) lead equivalency at 150 kilovolts peak (kVp) be available for use by persons who may receive exposure to x-rays in a medical facility.

General duties and reasonable precautions

The OHSA also contains a variety of general duties including the duty on employers to take every precaution reasonable in the circumstances for the protection of a worker.

As a general matter, what follows are examples of what may be considered to be reasonable precautions in the context of PPE in radiology.

Risk assessment and control

A comprehensive PPE program is important. The employer, designated competent person, supervisor or radiation protection officer (as per Regulation 543) should assess each worker’s need for protection according to the work he or she is required to perform in the required environment. The PPE program should include the following elements:

1. Policy – selection, fit-testing, wearing, inspection, maintenance, storage of PPE, and related training.
2. Roles and responsibilities - of workplace parties with respect to: risk assessment, hazard control analysis, selection of PPE, inspecting, training etc.
3. Risk assessment - identify radiation exposure hazard areas and assess potential for exposure.
4. Hazard control analysis - establish which control measures (e.g., engineering, administrative and work practices, PPE) are in place and used to minimize the exposure to x-rays. When control measures are not practicable or are not adequate to protect the worker, identify who is at risk of exposure – and to which degree parts of the body are exposed – and the level and type of PPE required.
5. PPE selection - ensure lead equivalency meets shielding requirements and PPE is labeled as doing so. The design, size and arrangement of PPE should be such that all of the organs and parts of the body which are intended to be protected are protected in all postures and work positions assumed by the worker during an x-ray procedure.
6. Fit testing - proper fit and mobility.
7. Storage - aprons, thyroid collars and gloves should be properly stored by hanging or draping over appropriate hangers.
8. Inspection and maintenance - check for defects, test shielding/attenuation provided by PPE to ensure that it meets lead equivalency, clean and repair defects not associated with the lead lining, e.g., clasps or Velcro straps.
9. Training - on selection, limitations, fit testing, storage, inspection, and maintenance.

Shielding provided by PPE

The shielding achieved by the PPE at a specific x-ray energy (expressed as kVp) should be as great as, or greater than, the shielding which would be achieved by a 0.5 mm thickness of non-alloyed lead at that same specific energy. This equivalency of shielding should be over the range of energies used in a particular room or application.

Types of PPE

Lead aprons and thyroid collars

The effectiveness of lead aprons and thyroid collars in reducing exposure to leakage or scatter radiation relates directly to their physical construction, fit, and how they are used.

Construction

Any toxic material used for the attenuation of x-rays in PPE should be sandwiched between inert material or encapsulated in a substance which does not allow the toxic material to come in contact with the wearer. The attenuating material should be affixed to the encapsulating material to prevent the material from sagging, delaminating, tearing or distorting over time.

Fit

The fit of the protective equipment should be such that all of the organs and parts of the body which are intended to be protected are protected in all postures and attitudes (relative orientation to the x-ray source or scattering object) assumed by the worker during an x-ray procedure. This may involve custom fitting; but at the very least, the worker should have a choice of sizes.

The fit of wrap-around aprons should be such that the overlapping material provides appropriate and adequate shielding. The area of the body covered by this material should include the entire front of the body (anterior surface) and should extend to the posterior midline of the body.

The thyroid collar and apron should fit together in a complementary fashion so that there are no gaps between them.

Use

If a worker’s duties necessitate turning his or her back to the scattering object (patient) for a significant portion of time (based on the risk assessment), the lateral and posterior layers of the protective equipment should provide appropriate and adequate shielding. In dose-intensive applications such as angiography, heart catheterization and interventional imaging, open-backed aprons are not acceptable for use by anyone other than the fluoroscopist controlling the foot pedal or exposure switch.

Ergonomic issues should be considered when purchasing an apron. Lumbar support in the form of weight belts and padded shoulders can improve the product comfort, and reduce the risk of back injury. Separate skirts and tops can redistribute weight so as to bear on several large body joints. Manufacturer’s instructions should be followed regarding maintenance and storage. For example, aprons should be hung up when not in use. They should never be folded, wrinkled or creased.

Leaded glasses

In procedures where scatter radiation to the lens of the eye could approach the annual dose equivalent limit of 150 millisieverts, as per Regulation 861, the use of leaded glasses is recommended.

Protective gloves

Protective gloves or gauntlets must possess at least 0.5 mm lead equivalency throughout the glove, including fingers and wrist, as per O. Reg. 67/93.

General PPE requirements

Labeling

PPE should be labeled with the lead-equivalent thickness of the material permanently and legibly marked as per Health Canada Safety Code 35. The specific room the apron is used in, or application the apron is used with, should also be specified on the label.

Verification of meeting Ministry of Labour shielding

Documentation that particular protective equipment provides appropriate and adequate shielding can be obtained from the vendor or manufacturer in the form of a certificate or by physical comparison testing. Verification testing could involve comparing the grey scale, optical density or radiation measurements between the protective equipment and a 0.5 mm thickness of non-alloyed lead over the range of energies (kVp) used in a particular room or application.

Quality assurance testing

It is generally an acceptable quality assurance practice to verify the integrity of the PPE every six months. This can often be done by a documented visual and tactile inspection. In addition, a documented fluoroscopic examination or written assessment of radiographic film(s) should be conducted at least annually or more frequently if use, conditions or other circumstances require. Records of testing, and follow-up documentation should be available on demand to Ministry of Labour inspectors. This is a general duty of an employer under clauses 25 (1) (a) and (b) of the OHSA.

Rejection criteria

Any protective equipment that exhibits visual, tactile or x-ray examination defects, must be repaired or replaced. This includes tears, separation from stitching, distortion producing a non-uniform attenuation and multiple pinholes or punctures.

In summary, lead apparel which contains defects such as holes or cracks should be decommissioned if the aggregate area of the holes or cracks exceeds those in the table below:

Maximum aggregate area of holes or cracks in lead protective apparel^[1]

Type of apparel	Total or aggregate area
Lead apron with built-in thyroid shield	10 cm2 whole-body 0.2 cm2 or 20 mm2 reproductive region 1 cm2 neck region
Separate thyroid shield	0.03 cm2 or 3 mm2
Gauntlet	3 cm2

^[1]Reference: Emerenciana Duran and Brian Phillips, Rejection Criteria For Defects In Lead Apparel Used For Radiation Protection Of X-ray Workers (PDF). Radiation Protection Services, BC Centre for Disease Control, March 1, 2003

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