ESTABLISHING DOSE REFERENCE LEVEL FOR COMPUTED TOMOGRAPHY (CT) EXAMINATIONS IN MALAYSIA

Presenter	:	ARIF BIN ABDULLAH
E-mail	:	-
Date	:	13 / 3 / 2009
Time	:	10.00 AM
Venue	:	MAKMAL CAI (258), ARAS 2, PUSAT PENGAJIAN SAINS FIZIK
Sypnosis	:	This study is conducted with the collaboration of the Malaysian Atomic Energy Licensing Board (AELB) in order to establish dose reference level (DRL) of 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 30 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 the ImPACT Dosimetry Calculator of both ImPACT CTDIair and measured CTDIair values as a comparison. This study found that 4% to 22% of deviations between both values and the deviation represent the dose influence factors contributed from the machine. Every protocol used at certain CT examinations were analysed and found that tube potential (kVp) was not the main contribution of effective doses deviation. Other scanning parameters such as tube current – time product (mAs), scan length and non-standardisation in some of the procedures were significant reasons in contributing 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 of routine head, routine chest and pelvis examinations are within the same range with studies conducted in the European guidelines, the UK and Taiwan. For the routine abdomen examinations, the effective dose is still within the range of the studies from European guidelines and Taiwan but 55.1% higher than the value from the study in the UK. Lastly, this study also provided the third quartile values of effective dose values for every CT examinations collected in this study so that they could be used as reference in establishing the dose reference level of CT examinations in Malaysia.

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