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ECR'2017 - Milton Santos


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Date 2017/03/01
Title A multi-site head CT topogram acquisition protocol analysis based on DICOM metadata
Speaker Milton Santos
Event ECR'2017
Location Vieena
Country Austria


Purpose: Several international initiatives and scientific studies emphasise the need to promote a greater focus on patient safety when choosing Computed Tomography (CT) scan parameters. This work aimed to analyse the CT Topogram dimension and scan parameters used in Head CT studies conducted in three distinct CT equipment and based on DICOM metadata stored at PACS facilities from two health institutions. Methods and Materials: The metadata produced by three different Computed Tomography (CT) equipment and stored in two health care PACS facilities were systematically analysed using a DICOM Metadata mining approach. For studies characterisation several DICOM tags were analysed (e.g. mAs, KvP, Exposure Time, Modality, Patient Age) within different queries. The CT Topogram dimension was obtained from the Exposure Time value and the table feed during the topograma acquisition. Results: The DICOM metadata from 1.274.927 images, bellowing to 19.180 studies performed on 16.169 patients (including 768 paediatric patients) were analysed. The number of CT Topogram images performed per patient ranged from 1 to 2,33 and its dimension between 20,76 cm and 25,16 cm depending on the equipment (CT1=20,8cm±0,04; CT2=24,01cm±0,4; CT3=25,01cm±0,5), namely in paediatrics studies (CT1=20,78cm±0,01; CT2=23,61cm±0,71; CT3=24,98cm±0,01). With regard to CT Topogram scan parameters, no significant changes were identified when the x-ray Tube Current (CT1=10mA±0,02; CT2=49,98 mA±0,03; CT3=39,47 mA±2,29) and KvP values were analysed (CT1= 119,54KvP±1,65; CT2=120,02KvP±0,04; CT3=90KvP). Conclusion: The age groups (including the paediatric patients) are not factors determining significant changes in the values of the exposure factors and size of the area exposed to radiation upon topogram acquisition.