EuroSafe Imaging 2020
Performed at one institution, Observational, Retrospective, Dosimetric comparison, Radiation safety, Dosimetry, CT, Radioprotection / Radiation dose, Oncology, Haematologic, Physics in Medical Imaging
M. Franchi, A. Depaoli, C. Guarnaccia, L. gianusso, O. Rampado, F. Darvizeh, R. ropolo, P. Fonio
Description of activity and work performed
Radiation exposure and both objective and subjective image quality were retrospectively evaluated for 30 patients who underwent WBLDCT.
CT scans were performed on a 256-slice CT scan.
The effective dose was estimated by Virtual Dose CT using data extracted from Physico Emme Esse software (as shown in Fig.2).
Patient effective dose due to WBLDCT was then compared with effective dose of 30 conventional X-ray examinations (Philips Digital Diagnost DR) which were calculated by Monte Carlo PCXMC program (as shown in Fig.3).
Objective image quality was evaluated based on noise measurements and contrast to noise ratio (CNR).
Furthermore, subjective image quality was assessed, using a five-point likert scale by two radiologists.
Eventually the inter-observer agreement on precence/absence of osteolitic lesion and image quality was tested by the Wilcoxon signed-rank test.
The median effective dose for WBLDCT was 1.9 mSv; lower than those reported in the literature for the same procedure and slightly higher than the median effective dose calculated for the skeletal survey (1.2 mSv).
Median noise measurements were in the range of 55-76 HU for soft tissue and 67-218 for bone.
The median CNR values were between 0.7 and 3.9, with the exception of the bone diaphysis with a range between 9.7 and 15.2 (as shown in Fig.5).
Image quality for all sites and patients was ranked between 4 (good) and 5 (very good).
The scores attributed by the readers to the presence/absence of lesions and to the image quality were in a good accordance with P-values > 0.1(as shown in Fig.6).