Abstract:
Introduction: The diagnostic reference levels (DRL) can be used to identify the
appropriate level of exposure for a given X-ray procedure. The DRL also defined per
standard patient or phantom to limit the effect of patient size on the radiation dose. The
definition of the standard patient varies from country to country. The Sri Lankan average
adult weighs 58 kg, while the average European weigh around 70 kg. Therefore, the
defined DRLs will be different since the exposures usually depend on the patients'
physique. The optimization of radiation dose requires a DRL comparison between different
countries with varying average adult populations. Therefore, such comparisons would
mislead the optimization process. The present study aimed to evaluate the impact of the
average adult definition on the calculated DRL
Material and Methods: The dose area product (DAP) data of seven X-ray projections
(cervical spine -AP/Lateral, abdomen AP, chest-PA, KUB and lumbar spine AP/Lateral)
belong to 235 adult patients (18-89 years) were filtered into two average adult groups of
weight 58 kg and 70 kg.
Results & Discussion: The percentage difference of the mean DAP (µGym 2 ) value
obtained for the groups mentioned above was found to vary between 2.7% to 67.0%. The
mean DAP value for the 58 kg group was consistently lower than that of the 70 kg group.
In addition, the resultant comparison of calculated IDRLs of two groups with the UK DRL
showed the varied degree of optimization requirements (between (-1.2%) to (+53.1%) and
(+2.3%) to (+64.2%) for group A and group B respectively).
Conclusion: Improper comparison of DRLs between different average adult populations
could adversely affect both patient radiation dose and image equality. Therefore, it is
recommend to compare DRLs between the countries with the same average adult
populations during optimization.
