Providing the metrology required to ensure patient safety during medical x-rays
Medical x-ray imaging constitutes the largest component of human exposure to artificial ionising radiation and radiation exposure from these procedures attributes to cancer risk. To help in reducing this risk, EC Directive 2013/59/Euratom stipulates that radiation doses, measured with dosimeters, be evaluated and optimised.
However, the difference in dosimeter response between laboratory calibration and clinical use is not well known.
IEC 61674 and TRS-457 define performance limit characteristics for diagnostic radiology dosimeters but fail to clearly distinguish between reference and field-class dosimeters and do not consider the characteristics of dosimeters currently on the market.
Semiconductor-based x-ray multimeters (XMMs) are the most common hospital dosimeters but no well-defined calibration or measurement procedures exist for them - meaning measurement traceability to the SI is often lacking.
This project will review a range of radiation fields relevant in medical imaging and produce a proposal to update the reference x-ray qualities used for x-ray calibrations and system testing.
The performance of commercial dosimeters used in calibration and clinical conditions will be investigated, establishing a clear-cut definition between reference and field-class dosimeters.
Calibration and measurement procedures for XMMs will be determined, giving an unbroken traceability chain for relevant clinical parameters. A comparison exercise will then be performed, ensuring that the newly established procedures provide consistent results.
Results will input into relevant standards, such as IEC 61674, providing the harmonised and standardised calibration and measurement procedures required to ensure traceability and accurate dosimetry, helping to prevent unnecessary radiation over-exposure to patients.