EN IEC 61331 Protective Devices Against Diagnostic Medical X-Radiation

The “EN IEC 61331 Medical X-ray Protective Devices for Diagnostic Purposes” standard, which is based on a European standard and subsequently published by the International Electrotechnical Commission (IEC), consists of the following sub-sections published under the same title:

• The standard “EN IEC 61331-1 Part 1: Determination of attenuation properties of materials” applies to sheet-form materials used in the manufacture of shielding devices against radiation qualities produced by X-ray tube voltages up to 400 kV and gamma radiation emitted by radionuclides with photon energies up to 1,3 MeV. This standard does not apply to shielding devices that need to be checked for the presence of attenuation properties before and after their service life.

This standard specifies methods for determining and demonstrating the weakening properties of materials. Weakening properties are given as follows:

• Weight loss rate
• Accumulation factor
• Weight loss equivalent

Where applicable, homogeneity and mass per unit area indicator.

This standard also includes methods for specifying the values ​​of attenuation characteristics that comply with this standard. The following are outside the scope of this standard:

• Periodic inspection methods for protective devices, especially protective clothing,
• Methods for determining attenuation by layers in radiation beams.
• Methods for determining attenuation for protection against ionizing radiation provided by walls and other parts of a facility.

In short, this standard defines standardized X-ray beam qualities (50-150 kV) and a wide beam geometry that simulates real clinical conditions. It specifies how to accurately measure lead equivalence (narrow beam tests are prohibited for final certification as they overestimate protection). It introduces the concept of attenuation ratio and minimum transmission limits.

• The standard “EN IEC 61331-2 Part 2: Translucent shielding plates” applies to semi-transparent shielding plates used for radiation protection in X-ray diagnostics and X-ray therapy. It also applies to semi-transparent shielding plates used for protection against gamma radiation in nuclear medicine and brachytherapy with automated controlled end-loading equipment.

This standard does not cover other translucent radiation shielding materials, for example:

• Leaded goggles or protective eyewear (glasses) to protect the operator's eyes.
• Lead-lined face shields that cover the operator's entire face.
• Patient eye protection
• Thyroid/neck protective devices.

This standard addresses the requirements for the following:

• Geometric accuracy
• Optical quality of the material
• Spectral conductivity
• Radiation attenuation properties
• Marking
• Declaration of conformity to this standard.

In short, this standard relates to transparent shields (lead acrylic, ceiling curtains, mobile barriers). The minimum lead equivalent is typically 0,50 mm Pb at 100-150 kV. For lead acrylic, the optical light transmittance is at least 80 percent. It includes mechanical drop tests and impact resistance requirements. It must remain crack-free and retain damping after aging tests.

• The standard “EN IEC 61331-3 Part 3: Protective clothing, goggles and protective patient shields” applies to protective devices such as protective clothing and goggles for the protection of individuals against X-ray radiation up to 150 kV during radiological examinations and interventional procedures. This standard addresses general requirements relating to accompanying documentation, design and materials used, sizing, specific design characteristics, minimum attenuation properties of materials, marking and standardized forms of declarations of conformity to this standard. It primarily covers protective clothing aimed at protecting the operator, for example:
• Protective aprons
• Thyroid collars
• Protective gloves
• Protective gloves
• Protective eyewear.

This standard also covers protective devices for patient protection, for example:

• Protective gonad aprons
• Scrotal shields
• Ovarian shields
• Shadow shields
• Protective gowns used in dentistry.

The second group of protective devices is designed for use during radiological examinations to minimize the effects of radiation on the reproductive organs, particularly in terms of genetic damage.

The latest revision of this standard includes the need for a better method for determining attenuation characteristics over a wider and more clinically relevant range of radiation quality suitable for the use of the devices. It also covers three additional protective devices: thyroid collars, protective eyewear, and protective gowns for dental use.

In short, this standard includes common lead equivalent values ​​and applications. Every garment must be permanently marked with the lead equivalent at the reference voltage (e.g., 0,35 mm Pb at 100 kV). Overlapping areas in wrap-around aprons must maintain at least the stated equivalent. Manufacturers must declare whether the material is lead-based or lead-free/composite.

In conclusion, the EN IEC 61331 standards are an internationally recognized standard regulating the performance and testing of all protective materials and devices used to protect patients and healthcare workers from scattered diagnostic X-ray radiation (typically 50-150 kV). These standards have been harmonized in Europe and form the technical backbone of CE marking for X-ray protective equipment worldwide.

Diagnostic X-ray procedures remain the largest source of man-made radiation exposure for the general population. While primary radiation exposure can be avoided, scattered radiation can reach personnel and patients. The EN IEC 61331 standard guarantees that every protective garment or shield sold actually attenuates X-rays as claimed on its label (typically expressed as “mm Pb” or lead equivalent).

EN IEC 61331 standards remain the gold standard, guaranteeing that X-ray protective gowns, shields, and goggles sold anywhere in the world actually deliver the radiation protection promised on the label. Familiarity with these three components is essential for radiologists, medical physicists, radiation safety officers, and procurement teams to make evidence-based purchasing decisions and maintain regulatory compliance.

In European Union countries, CE marking is mandatory under the Medical Devices Regulation (MDR). While the FDA in the US still refers to the older 21 CFR values, most modern manufacturers voluntarily comply with the IEC 61331 standard for global market access.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "EN IEC 61331 Protective devices against diagnostic medical X-ray radiation" standard.