Document Type : Original Paper
Authors
1
Laboratory of Electronic Systems, Information Processing, Mechanics and Energetics, Faculty of Sciences , University Ibn Tofail Kenitra, Kenitra, Morocco
2
Hassan First University of Settat, High Institute of Health Sciences, Laboratory of Sciences and Health Technologies, Settat, Morocco
3
Departement of Physics, Laboratory of High Energy Physics, Modelling and Simulation, Faculty of Science, Mohammed V Agdal University, Rabat, Kingdom of Morocco
Abstract
Introduction
The optimization of radiation exposure when exploring small and complex anatomical structures is the most important issue for temporal bone CT. The objective of this study is to use single-shot volume acquisition in order to minimize the dose and compare the obtained image quality to a conventional helical technique.
Material and methods: Twenty patients (8 males, 12 females) were scanned using the 135kVp single-shot volume mode (VMCT135-kVp) whereas another twenty patients (9 males, 11 females) were examined using the 120kVp helical mode (HMCT120-kVp). A physician-interpreter evaluated the subjective conspicuity of 53 structures in the temporal bone on a 5-point scale using multiplanar reconstruction (MPR).
Results
The mean dose-length-product (DLP) for the VMCT135-kVp was (69.6±2.5 mGy.cm), which was significantly lower (p<0.001), compared to (186.4±4.3 mGy.cm) for HMCT120-kVp. Similarly, the effective dose (0.15±0.01 mSv) for VMCT135-kVp was reduced by approximately 61.5% relative to the effective dose (0.39±0.05 mSv) for HMCT120-kVp. The effective radiation doses using VMCT135-kVp scans were still lower compared with those of literature-based protocols. In contrast, there was no significant difference in the image noise average between the two protocols (p> 0.05). Indeed, Overall analysis of the 53 anatomic structures revealed no differences between the two protocols, and most anatomic structures were identifiable. Furthermore, when we compared the anatomic structures separately, the analysis showed that the image quality scores of some Organ structures, permitted better visualization in the VMCT135-kVp scan.
Conclusion
For temporal bone tomography, the VMCT135-kVp scan significantly reduce radiation exposure compared to the conventional HMCT120-kVp scanning mode. The obtained dose was lower compared with the literature-based protocol while maintaining image visualization quality. The dose optimisation and imaging acquisition time reduction of 0.5 s in VMCT135-kVp are particularly advantageous when scanning children and uncooperative patients.
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