EN ISO 18090-1:2026

Overview

EN ISO 18090-1:2026 is an international standard developed by CEN in collaboration with ISO, focusing on the characteristics of reference pulsed photon radiation for radiological protection. Specifically, it defines how to characterize, calibrate, and test photon pulsed X-radiation, with pulse durations ranging from 0.1 ms to 10 s. This duration range encompasses most medical diagnostic X-ray pulses, making the standard highly relevant for healthcare, testing laboratories, and equipment manufacturers. EN ISO 18090-1:2026 ensures consistent practices and reliable dosimetry in environments where pulsed X-radiation is used.

Key Topics

• Scope and Applicability

  • Applies to pulsed X-radiation with pulse durations from 0.1 ms to 10 s
  • Covers the requirements for reference fields used in the calibration of radiation protection instrumentation
  • Some specifications can be applied to much shorter pulses (e.g., from X-ray flash units or femtosecond lasers), but certain parameters may not be measurable for these extremely short durations

• Radiation Characteristics

  • Time-dependent behaviour of air kerma rate: Analysis of how the air kerma rate (energy delivered by photon radiation per unit mass of air) changes over the pulse
  • Time-dependent X-ray tube high voltage: Measurement of high voltage supplied to the X-ray tube throughout the pulse
  • Uniformity of air kerma rate: Cross-sectional uniformity of the radiation beam
  • Air kerma and air kerma rate per pulse: Evaluation of the radiation dose delivered in single pulses
  • Repetition frequency: Relevant for repeated pulses, important in certain medical procedures

• Calibration and Testing Requirements

  • Establishes methods for ensuring radiation protection dosimeters and dose rate meters respond accurately to pulsed radiation
  • Utilizes reference radiation qualities defined in existing ISO and IEC standards (no new radiation qualities are introduced)
  • Details parameter limits needed for valid calibration
  • Reference is made to conversion coefficients from ISO 4037 for phantom-related quantities

• Measurement Techniques

  • Highlights the challenge of measuring single pulses and the increased complexity over continuous radiation
  • Addresses the importance of time and space-resolved measurements, as well as synchronization and proper instrument calibration

Applications

• Medical Diagnostics

  • Calibration of dosemeters for X-ray equipment in hospitals and clinics
  • Ensures accurate patient and occupational dose assessments for pulsed imaging modalities including fluoroscopy and computed tomography (CT)

• Testing and Certification Laboratories

  • Used as the reference for establishing traceable calibration services for pulsed X-radiation
  • Forms the technical basis for type testing and performance verification of radiation protection instruments

• Equipment Manufacturers

  • Assists in designing and validating the performance of new dosimeters and dose rate meters for pulsed photon fields
  • Ensures compliance with international best practices for electromagnetic compatibility and safety in radiological protection

• Research and Development

  • Reference for studies involving high-intensity or ultra-short pulse X-ray sources such as femtosecond lasers or X-ray flash units
  • Supports scientific investigations into dosimetry under pulsed photon radiation conditions

Related Standards

• ISO 4037 Series: X and gamma reference radiation for calibrating dosemeters and dose rate meters, including conversion coefficients for phantom-related quantities
• IEC 61267: Radiation conditions for medical diagnostic X-ray equipment, relevant for establishing radiation qualities and filtration requirements
• IEC/TS 62743, IEC/TS 63050: Electronic dosemeters and their performance in pulsed fields, referenced for performance requirements
• EN ISO 18090 Series: Additional parts addressing other types of pulsed radiation or measurement contexts

By following EN ISO 18090-1:2026, organizations and professionals in radiological protection can ensure robust, traceable dosimetry practices for pulsed photon radiation, supporting safety, regulatory compliance, and optimization in medical and technical applications.