Assessment of patient dose and noise level of clinical CT images: automated measurements

We investigated comparisons between patient dose and noise in pelvic, abdominal, thoracic and head
CT images using an automatic method. 113 patient images (37 pelvis, 34 abdominal, 25 thoracic, and
17 head examinations) were retrospectively and automatically examined in this study.
Water-equivalent diameter (Dw), size-specific dose estimates (SSDE) and noise were automatically
calculated from the center slice for every patient image. The Dw was calculated based on
auto-contouring of the patients ’ edges, and the SSDE was calculated as the product of the volume CT
dose index (CTDIvol) extracted from the Digital Imaging and Communications in Medicine (DICOM)
header and the size conversion factor based on the Dw obtained from AAPM 204. The noise was
automatically measured as a minimum standard deviation in the map of standard deviations. A square
region of interest of about 1 cm 2 was used in the automated noise measurement. The SSDE values for
the pelvis, abdomen, thorax,...

Source: Journal of Radiological Protection - July 3, 2019 Category: Physics Authors: Choirul Anam, Wahyu Setia Budi, Kusworo Adi, Heri Sutanto, Freddy Haryanto, Mohd Hanafi Ali, Toshioh Fujibuchi and Geoff Dougherty Source Type: research