Calibration of reference standards used for dosimetry measurements

Dosimeters used to measure radiation at laboratories, hospitals and in the field must be calibrated against a national standard to ensure that measurement results are consistent with the International System of Units (SI). The IAEA calibrates national reference dosimeters, linking radiation dosimetry in Member States to the SI.

Accurate radiation dosimetry is required for different applications and is essential in radiation therapy of cancer patients. It is also needed in many other areas, such as the optimization of radiation imaging for diagnostic radiology and nuclear medicine, and the radiation protection of staff, patients and the public. Accurate radiation dosimetry is achieved only through the use of calibrated dosimeters.

The quantities used for radiation dose measurements are established in Primary Standards Dosimetry Laboratories. These labs provide calibrations of reference dosimeters of Secondary Standards Dosimetry Laboratories. Secondary standards labs in turn calibrate dosimeters of end users, such as hospital staff. This entire process is called the traceability chain.

The IAEA maintains the Dosimetry Laboratory in Seibersdorf, Austria, which is the central laboratory of the IAEA/WHO Network of Secondary Standards Dosimetry Laboratories. National standards laboratories in Member States send their reference dosimeters in for calibration and receive a calibration certificate. In this way, the IAEA establishes the link of radiation dosimetry in Member States to the SI. The IAEA Laboratory’s calibration services are used for dosimetry measurements in radiation therapy, diagnostic radiology and radiation protection.

In addition, the IAEA also conducts bilateral comparisons with national standards labs to assess their performance. This ensures that the determined dose levels are internationally comparable to results obtained in other countries.