ICRP Publication 135: Diagnostic Reference Levels in Medical Imaging

Abstract

The International Commission on Radiological Protection (ICRP) first introduced the term ‘diagnostic reference level’ (DRL) in 1996 in Publication 73. The concept was subsequently developed further, and practical guidance was provided in 2001. The DRL has been proven to be an effective tool that aids in optimisation of protection in the medical exposure of patients for diagnostic and interventional procedures. However, with time, it has become evident that additional advice is needed. There are issues related to definitions of the terms used in previous guidance, determination of the values for DRLs, the appropriate interval for re-evaluating and updating these values, appropriate use of DRLs in clinical practice, methods for practical application of DRLs, and application of the DRL concept to newer imaging technologies. This publication is intended as a further source of information and guidance on these issues. Some terminology has been clarified. In addition, this publication recommends quantities for use as DRLs for various imaging modalities, and provides information on the use of DRLs for interventional procedures and in paediatric imaging. It suggests modifications in the conduct of DRL surveys that take advantage of automated reporting of radiation-dose-related quantities, and highlights the importance of including information on DRLs in training programmes for healthcare workers. The target audience for this publication is national, regional, and local authorities; professional societies; and facilities that use ionising radiation for medical purposes, and responsible staff within these facilities. A full set of the Commission’s recommendations is provided.

Defining a national reference level for intraoperative radiation exposure in urological procedures: FLASH, a retrospective multicentre UK study

“…As per the Health Protection Agency and the ICRP , diagnostic reference levels for DAP and FT were calculated from the 75th percentile of median values from each centre.…”

“…The IRMER state that investigations must be assigned a reasonable radiation exposure, the ‘diagnostic reference level’ . The ICRP have recently published a guide to these diagnostic reference levels and how to obtain them from a sample of representative centres.…”

Diagnostic reference levels for 18F‐FDG whole body PET/CT procedures: Results from a survey of 12 centres in Australia and New Zealand

“…Thus, reporting effective dose values is important to reflect the actual radiation doses delivered from PET/CT acquisition protocols. Although effective dose is not appropriate unit for a DRL, effective dose is the only convenient unit that enables combined radiation doses and the conversion of the value into one unit (mSv) . The total effective dose delivered from additional CTs delivered from some AU QLD PET/CT centres were higher than delivered from a breath‐hold CT acquisition protocol from three NZ PET/CT clinical centres.…”

“…These levels are anticipated not to exceed the 75 th percentile of the recommended NDRL standard for diagnostic procedures when good and normal practice is applied. Clinical facilities with a median emergent dose that is higher than the national 75 th percentile dose should consider methods of optimizing their clinical imaging protocols to minimize the radiation doses delivered to the patients …”

“…Published articles reported 18 F‐FDG PET/CT DRL values for the administered activity or CT used for AC and anatomical localization purposes, with few authors reporting both radiation doses . PET/CT DRLs from both radiation sources should be reported to provide suitable guidelines for professionals . In 2005, two PET/CT centres in NZ have performed PET/CT examinations with new PET/CT centres planned to start PET/CT services in the coming 5 to 10 years .…”