Computed tomography (CT) has been used in medicine since 1970s and is now firmly established as an essential tool for medical diagnosis and therapy.
On that context,
there has been a marked and steady increase in numbers and the use of CT in the past two decade (1),
and it,
now,
accounts for more than half of the medical radiation exposure of the European population in 2007-2010 (2). In Turkey,
in particular,
the number of CT scanners are still below OECD averages.
On that context,
the average number of CT scanners is 25.7 per million people in OECD,
whereas it is only 14.3 per million people in Turkey.
The difference between OECD countries and Turkey,
become reversed when considering number of scans per capita.
In Turkey 175 CT examinations were performed per thousand people during 2015.
This number was only 142 in OECD on average (3).
The higher number of CT scans per capita points to the possibility that CT has even higher share of per capita medical radiation exposure to Turkish than average European population.
To complicate the matter further, the discordance between per capita number of scanners and examinations exerts a major pressure on CT scanners,
resulting in nonstandartised imaging in many instances.
Increased collective dose levels that are mainly due to CT examinations are known to increase the incidence of late stochastic effects seen as malignancies,
teratogenic disorders and mutations.
(4).
CT technique -apart from its adverse effects that were briefly described above,
provide great benefits to patients when medically justified and properly conducted.
However,
the associated radiation exposures have to be monitored and optimized,
in view of their potential to cause harmful health effects.
This duty is clearly sated in international BSS Req.
38 as “Registrants and licensees and radiological medical practitioners shall ensure that protection and safety is optimized for each medical exposure” (5).
The concept of the Diagnostic Reference Level (DRL), as an investigation tool to identify situations where patient doses are unusually high and need to be reduced,
was adopted by the International Commission on Radiological Protection in ICRP Publications 60 and 73 and by the European Directive 97/43/Euratom.
DRLs are values which are usually easy to measure and have a direct link with patient doses.
They are therefore established to aid efficient dose management and to optimize patient doses. DRLs should not to be exceeded for standard procedures when good and normal practiceis performed If patient doses are found to exceed consistently the corresponding reference level, investigation and appropriate corrective action should be taken,
unless the unusually high doses could be clinically or technically justified.
As a part of proper radiation protection program,
and according to Radiation Protection 109 (EC 1999),
Guidance on Diagnostic Reference Levels (DRLs) for Medical Exposures (6),
these levels should be established, have to be revised periodically,
and be specific to a country or region because published DRLs values from other countries (with potentially different imaging practices and technology) may not be relevant to other countries’ particular circumstances.Locally it is possible to establish DRLs to compare practices in a hospital or between hospitals on a hospital district.
In such cases,
local DRLs should be more stringent or equal to the national or regional DRLs,
if available.
The aim of this paper is to to establish DRLs to compare practices between various representative EuroSafe Imaging Star (*****) hospitals of the largest healthcare district in Turkey.
There are no established national DRLs in that country,
and the data obtained in that context will provide a firm basis to establish such levels.