Despite the recommendations and the clear need for DRLs for radiological examinations,
only very few DRL data are available and they are only set in a particular radiological examination or in a small region of the county.
The reasons for this are many-fold: patient dose levels vary considerably as a function of age,
size or weight of the patients and therefore,
DRLs for age,
size or weight groups need to be defined; due to the lack of standardization of these groups,
the comparison of DRLs or patient dose data with other countries is not straightforward; due to the general paucity of patient dose data for radiologic examinations,
it is often difficult to collect sufficient data to establish DRLs,
or to compare local values with established DRLs,
for each age or weight sub-group.
Patient dose surveys are needed to establish DRLs,
and there is little guidance on the statistical requirements for such surveys and on how to derive the DRL values.
Special challenges may be introduced by different institutions,
e.g.
the procedures in a specialty cancer center might require different DRLs compared to those in a more general institution.
Further,
the rapidly evolving technology may complicate the establishment of DRLs.
While there are clear benefits of establishing and using DRLs in radiological examinations,
these have not been implemented in an optimal way,
and there have been several shortcomings and limitations justifying additional considerations and guidance to be taken.
While the physical quantity and the patient grouping (mainly by age) selected for the DRL settings have usually been reported exactly,
the background information on the patient dose collection is often only briefly reported or not described at all.
Few reports provide exact information on the practical methods of data collection,
and the coverage of the imaging institutions (types,
a percentage of total) and the imaging practices have been reported in only a few countries.
Most probably,
data was collected manually,
occasionally not well controlled,
and possibly hampered by human errors.
The patient dose surveys required for setting DRLs are resource demanding and time-consuming,
in particular,
because the main methods of data collection still rely on the manual or semi-manual compilation.
Patient dose analysis is also difficult because there is often a lack of standardization in the specification of a given examination.
This makes comparisons of DRLs difficult and sometimes not relevant.
In order to establish the regional/local dose reference levels,
patient radiation dose data set needs to be created for different radiological examinations after optimizing the protocols followed for various procedures.
Optimizing the practices based on the shortcomings inferred from the initial observations and dose measurements helped to bring down the patient doses.
Regular update of knowledge and training enabled the radiation professionals to perform the radiological examinations with lower radiation dose to the patients as well as to themselves.
As inferred from this study,
we may further reduce the radiation doses to patients as well as professionals by optimizing the practices,
improving the radiation safety and protection awareness and hence the confidence in practice and adopting advanced technology.
The quality assurance and quality control of all radiation equipment need to be regularly verified and strictly adhered.
As observed from the literature review,
regular follow up help in significantly reducing the set DRLs.
A large scale multi-centric study in the region is highly recommended so that the cumulative population radiation dose may be reduced.