EuroSafe Imaging 2019
Action 4 - Dose management systems, Action 1 - Guidelines, implementation policies, and Clinical Decision Support (ESR iGuide), Computer applications, Radioprotection / Radiation dose, CT, Technical aspects, Radiation safety, Quality assurance, Education and training
B. Carey, C. Kennedy, R. Kavanagh, N. Moore, M. A. Maher, O. O’Connor, S. O'Neill
Description of activity and work performed
The objective of this study was to evaluate the potential for the use of body mass index (BMI) as an alternate size metric to effective diameter in order to allow calculation of size-specific dose estimate in CT.
50 adult patients were included in the study. All patients underwent a CT scan of the abdomen and pelvis with set parameters (Fig.
1). Dose length product (DLP) and volume computed tomography dose index (CTDIvol) values,
as well as the corresponding phantom size,
were recorded from each CT dose report. Size specific dose estimates (SSDE) were calculated by multiplying the CTDIvol for each patient by conversion factors corresponding to the effective patient diameters in the AAPM reference tables (Fig.
3). Each patient had their BMI calculated immediately prior to CT scan using a dedicated calibrated measuring device. Maximum skin-to-skin anteroposterior (DAP) and lateral (DLAT) diameters were measured in centimetres on lateral and anteroposterior localiser images,
2). Effective diameter (DE) is calculated as the geometric mean of DAP and DLAT (i.e.
DE = √(DAP x DLAT)