Radiation levels due to medical use are relatively low in the Netherlands compared to other countries1. In a recent review2 about dose reducing measures in children it appeared that Diagnostic Reference Levels (DRLs) for children were only used in about 50% of hospitals in the Netherlands.
This low percentage is in clear contradiction with the fact that most health professionals consider DRLs as a powerful means to optimize radiation dose.
So there seems to be opportunities for further optimization of the radiation dose in paediatric radiological practice.
Radiation protection is regulated in the Basic Safety Standards (BSS),
issued by the European Union (Euratom). The BSS for protection against the dangers arising from exposure to ionizing radiation are recently renewed (European Directive 2013/59/Euratom).
These new Standards should be effective in the form of national legislation by 2018.
The renewed directive,
strengthens (among others) requirements for the use of diagnostic reference levels (article 56.2) and written protocols (article 58a).
Besides that,
the role of the medical physicist in optimization processes is established (article 57.1b).
These topics are not completely new; they were already an item in the former Basic Safety Standard (European Directive 1998/96/29/Euratom).
In order to find out why the use of DRLs in children in the Netherlands is that low we reviewed applicable reports of the National Institute for Public Health and the Environment (RIVM).
Radiation levels in medical use are in large part determined by the quality of the equipment and the professionals involved in producing the image: radiologists and technicians.
The pillars for radiation protection are justification and optimization,
or in one acronym: ALARA (As Low As Reasonably Achievable).
However adhering to the ALARA-principle in the local situation doesn't mean automatically that all regional or national exposures are in the same range.
Diagnostic Reference Levels offer an opportunity to benchmark ones dose levels to the 75-percentile of the mean "national" dose or an expert judgement.
diagnostic reference levels.
The diagnostic reference level is a value for the exposure of a standard patient that still can be considered as ‘good medical practice’.
Diagnostic reference levels should not be exceeded in standard procedures associated to common clinical referrals and good diagnostic and technical performance.
In case it is observed that a diagnostic reference level is exceeded,
than it is expected that the user takes additional measures to achieve appropriate optimization of the concerning (and comparable) practices.
A diagnostic reference level is explicitly not a dose limit and is not applicable to individual patients.
It is applicable to the standard patient (in practice,
to be deduced from a group of patients) or to standard phantoms.
June 2012 the report "Diagnostische referentie niveaus in Nederland" (Diagnostic Reference Levels in the Netherlands) was published by a subcommittee of the Netherlands Commission on Radiation Dosimetry (NCS) with the aim to describe
(1) incorporation of diagnostic reference levels within the existing systems of quality assurance,
(2) the dose quantities of the reference levels and a brief description of the methods for measuring dose values,
and
(3) achievable dose levels for the exposure of patients that are associated to optimized practices.
implementation of DRLs
In an inventory3 by the RIVM in july 2013 it appaered that one year after this official introduction of DRLs,
more than 50% of hospitals used DRLs for adults but only 25% for children.
One year later in another selection of hospitals the percentage of DRLs in paediatric radiology was 50%,
but in 25% the DRLs were not used in the right way.
DRLs will be obligatory after 2018 due to the former mentioned European legislation:
Member States shall ensure the establishment,
regular review and use of diagnostic reference levels for radiodiagnostic examinations,
having regard to the recommended European diagnostic reference levels where available,
and where appropriate,
for interventional radiology procedures,
and the availability of guidance for this purpose (BSS,
Article 56.2).