Overview
EN ISO 13304-2:2022 - "Radiological protection - Minimum criteria for electron paramagnetic resonance (EPR) spectroscopy for retrospective dosimetry - Part 2: Ex vivo human tooth enamel dosimetry" sets minimum quality, measurement and reporting criteria for estimating absorbed ionizing radiation dose using ex vivo X‑band EPR spectroscopy on human tooth enamel (hydroxyapatite). The standard is intended to harmonize practice, enable inter‑laboratory comparison and ensure traceable, defensible dose estimates. It explicitly covers absorbed dose determination in tooth enamel and does not address conversion to organ or whole‑body dose.
Key topics and technical requirements
The standard defines minimum criteria across the full measurement workflow, including:
- Responsibilities of the customer and service laboratory (scope of service, sample information).
- Confidentiality and ethical considerations for handling human tooth material.
- Laboratory safety requirements (magnetic field, electromagnetic frequencies, chemical/biological and optical hazards).
- Apparatus and spectrometer requirements (EPR spectrometer sensitivity, microwave bridge, magnetic field and resonator considerations).
- Sample preparation (enamel extraction, applicable grain size and sample mass considerations).
- Measurement parameters and acquisition conditions: microwave power, magnetic centre field, sweep width and time, modulation amplitude, time constant, resolution, conversion time, number of accumulations, sample positioning and use of standards.
- Signal evaluation: assessment of radiation‑induced signal (RIS) intensity, intrinsic signals from resonator/sample tube and signal processing.
- Calibration: irradiation of calibration samples for low LET exposure and conversion of RIS intensity to absorbed dose.
- Uncertainty and performance testing: calculation of dose uncertainty, minimum detectable dose and performance checks (including inter‑laboratory comparisons).
- Quality assurance and control (QA/QC), documentation, sample collection/identification, transport and storage.
Practical applications
This standard is used where retrospective dose reconstruction from human teeth is required:
- Emergency response and triage after radiological/nuclear incidents
- Radiation epidemiology and retrospective exposure assessment
- Forensic dosimetry and investigative casework
- Research laboratories developing or validating EPR dosimetry methods
- Inter‑laboratory proficiency testing and method standardization
Who should use this standard
- EPR dosimetry service laboratories and measurement labs
- Radiological protection professionals and health physicists
- Forensic scientists and epidemiologists conducting exposure reconstructions
- Laboratory managers establishing QA/QC and validation procedures
- Regulatory bodies assessing laboratory competence and comparability
Related standards
- ISO/CEN standards on radiological protection and radiation measurements, and other parts of the ISO 13304 series (see national standards body for full listings). Use this document alongside applicable national regulations for handling human tissue and radiological samples.
Keywords: EN ISO 13304-2:2022, EPR spectroscopy, ex vivo tooth enamel dosimetry, retrospective dosimetry, absorbed dose, QA/QC, calibration, dose uncertainty.