Overview
EN ISO 16645:2019 (identical to ISO 16645:2016) provides requirements and recommendations for radiological protection and shielding design of medical electron linear accelerators. It applies to clinical accelerators with nominal beam energies from 4 MV to 30 MV, including special installations such as robotic-arm systems, helical IMRT devices, and dedicated intra‑operative radiotherapy (IORT) electron units. The standard excludes cyclotrons and synchrotrons used for hadrontherapy.
Keywords: ISO 16645:2016, EN ISO 16645:2019, radiological protection, medical electron accelerators, shielding design.
Key topics and technical requirements
The standard covers practical and technical aspects of shielding design and evaluation, including:
- Shielding design goals and assumptions - target dose limits, occupancy factors and design objectives to meet regulatory requirements.
- Roles and responsibilities - expectations for manufacturers, shielding-material vendors, architectural/contracting teams, the radiation protection officer (RPO) or qualified expert, and the licensee.
- Radiation fields around accelerators - characterization of primary X‑ray beams, bremsstrahlung from primary electron beams, secondary and tertiary X‑rays, neutrons (direct, scattered, thermal), and associated gamma radiation.
- Shielding materials and transmission values - guidance on acceptable materials and their transmission behaviour (attenuation).
- Shielding calculation methods - general formalism and computation approaches for:
- Primary and secondary barriers (single- and multi-layer)
- Maze geometries, doors and direct-shielded entrances
- Special device configurations (robotic arms, helical IMRT, IORT)
- Ducts and penetrations and their impact on radiation protection
- Radiological monitoring and measurements - recommended measurements for verification and quality assurance of shielding performance.
Keywords: shielding calculations, neutron radiation, maze, doors, ducts, shielding materials.
Practical applications - who uses this standard
ISO 16645 is intended for professionals involved in the planning, design, installation and operation of medical electron accelerators:
- Radiation protection officers (RPOs) and qualified experts preparing shielding designs and compliance reports
- Medical physicists conducting shielding calculations and post-installation measurements
- Linear accelerator manufacturers and vendors advising on room design and safety features
- Architects, builders and contractors constructing treatment rooms and maze/door assemblies
- Facility planners and licensees ensuring regulatory compliance and safe clinical operation
Keywords: medical physicist, radiation protection officer, facility planning, shielding design.
Related standards (high level)
- National/regulatory radiation protection limits and building codes
- Complementary ISO and CEN standards on radiological protection and equipment safety (consult local standards bodies for specifics)
This summary helps teams apply EN ISO 16645:2019 / ISO 16645:2016 for robust, compliant shielding design of clinical electron accelerators.