Establishing how patient size and degree of miscentring affect CTDI, using patient data from a dose tracking system.

Objectives: The work aimed to investigate and model the relationship between CT dose index (CTDI), patient size and miscentring metrics using data extracted from a dose tracking software tool. Further, using the established model we aimed to extract and estimate further AEC metrics and, finally, demonstrate how the CTDI may vary across a range of imaging exams and with variations in patient size, positional metrics and with scan parameters.

Methods: CT scan parameters, patient dose metrics, patient positioning information and patient and water equivalent diameter information was extracted from abdomen, thorax-abdomen-pelvis and thorax imaging exams acquired on a 128-slice Siemens Somatom Definition AS + CT system using dose tracking software over a 1 year period.