Multicentre Audit of Paediatric Brain Computed Tomography Dosage in Hong Kong: the Common Mistakes We Make

Full Article

YH Woo, YC Wong, E Kan, WSA Au-yeung, SMP Yu, KC Wong, YHJ Hui

Hong Kong J Radiol 2013;16:34-40

DOI: 10.12809/hkjr1312129

Objective: By auditing paediatric brain computed tomography (CT) performed in four Hong Kong centres, dosage values were obtained to address local practice and suggest improvements.

Methods:This was a retrospective review of plain CT brain studies on patients aged 16 years or below performed in four Hong Kong hospitals. During the 3-month audit periods in 2010 to 2011, patient demographic data and CT dosage using CT dose index volume (CTDIvol) and dose-length product (DLP) as measures were recorded for each paediatric brain CT case in each participating centre. Subgroup analyses (age of <1, 1-5, 6-10, 11-16 years) with mean, standard deviation, and third quartile were performed.

Results:Altogether 463 CTs from the four centres were studied. Overall mean and third quartile results for CTDIvol and DLP in each age-group were generally comparable to international standards. However, excessive dosages were occasionally noted in individual age-groups or centres. In all, 47 (10.2%) of the CTs entailed excessive dosages, with repeated scanning due to motion artefact being the commonest reason. Incorrect use of adult (instead of paediatric) CT protocols, and excessive scan ranges (outside the region of interest) were also frequent mistakes. In one centre, significantly increased dosages were detected immediately after the installation of a new CT machine.

Conclusions:Our results highlight the importance of adequate sedation in the paediatric age-group. Strict adherence to paediatric protocols and narrowing the scan range should also be emphasised. Departmental imaging protocols should be regularly reviewed to monitor dosage, especially after installation of a new CT scanner.



於香港多個中心進行有關兒童腦部計算機斷層掃描劑量的審核: 常見錯誤


目的:於香港四所小兒腦部計算機斷層掃描(CT)中心進行劑量審計,以了解本地醫院的表現,並 提出改善的建議。

方法:回顧研究於四家香港醫院接受腦部CT平掃的16歲或以下的兒童。從2010到2011年的三個月審 計期限,於每所中心找出有關病人人口數據的資料,記錄容積CT劑量指數(CTDIvol)和劑量長度乘 積(DLP)以作為輻射劑量的評估參數。然後進行亞組分析(即年齡為<1、1-5、6-10、11-16歲)找 出平均值、標準偏差和第三四分位數。

結果:研究了四所中心共463個腦CT掃描。CTDIvol和DLP在各年齡組別的總平均值和第三四分位 數值均與國際標準大致相若。可是偶爾會發現在個別中心或年齡組別中有超劑量的情況。共47 (10.2%)個病例牽涉超劑量,最普遍的原因是由於運動偽影而需重複掃描。此外,錯誤使用成人方 案(而非小兒方案)以及掃描範圍過大(超出感興趣區),也是常見的錯誤。亦有一所中心在安裝 新CT機後出現輻射劑量明顯加大的例子。

結論:研究結果顯示在兒童組別中使用足夠的鎮靜劑很重要。並應強調嚴格遵守使用小兒模式及縮 小掃描範圍。應定期審視部門的CT掃描方案以監測輻射劑量,特別是在安裝新CT掃描儀器後。