Establishing dose reference level for computed tomography (CT) examinations in Malaysia
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Date
2009
Authors
Abdullah, Arif
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Abstract
This study is conducted with the collaboration of the Malaysian Atomic Energy
Licensing Board (AELB) in order to establish dose reference level (DRL) for computed
tomography (CT) examinations in Malaysia. 426 examinations for standard adult
patients and 26 examinations for paediatric patients comprising different types of CT
examinations were collected from 33 out of 109 (30.3%) hospitals that have CT
scanner in Malaysia. Measurements of Computed Tomography Dose Index in air
(CTDIair) were done at every CT scanner in the hospitals that were involved in this
study to investigate the scanner-specific values comparable to the data published by
the ImPACT. Effective doses for all CT examinations were calculated using ImPACT
Dosimetry Calculator for both ImPACT CTDIair and measured CTDIair values as a
comparison. This study found that 4% to 22% of deviations between both values and
the deviations represent the dose influence factors contributed by the CT machines.
Every protocol used at certain CT examinations were analysed and it was found that
tube potential (kVp) was not the main contribution for effective doses deviation. Other
scanning parameters such as tube current – time product (mAs), scan length and nonstandardisation
in some of the procedures were significant contributors to the effective
dose deviations in most of the CT examinations. Effective doses calculated using
ImPACT CTDIair were used to compare with other studies to provide an overview of CT
practice in Malaysia. Effective doses for examinations of routine head, routine chest
and pelvis are within the same range with studies conducted for the European
guidelines, the UK and Taiwan. For the routine abdomen examination, the effective
dose is still within the range compared to the studies for European guidelines and
Taiwan, but 55.1% higher than the value from the study conducted in the UK. Lastly,
this study also provided the third quartile values of effective doses for every CT
examination collected in this study so that they could be used as reference in
establishing the dose reference level of CT examinations in Malaysia.
Description
Master
Keywords
Science Physic , Dose reference level , Computed tomography (CT) examinations