Recently, the radiology community has spent significant effort to optimize the radiation dose from CT to ensure patient safety while keeping the highest possible diagnostic information [1-3]. The purpose of our study was to compare and harmonize the image quality of head protocol on two CT scanners based on phantom scans to achieve the best possible image quality applying the lowest dose. In 2019, we have already evaluated the effective dose and image quality (IQ) of our abdominal CT study [4.].

everal scans were performed with Catphan 504 phantom on the GE LightSpeed VLC (CT1) and the Siemens Somatom Definition (CT2) CTs applying the routine head protocols for both scanners. In our Radiology Department, the head protocol was performed with 120 kV, X-ray current was set between 100-400 mA, the scan type was axial and slice thickness was 5 mm. These parameters were the same in every scan. We varied the noise index (NI- 2.3, 2.8, 3.3), the dose reduction factor (DRF- 20%, 30%, 40%)- and...

Figure 2., 3., 4. and 5. demonstrate the CNR values of different materials, relating to the different scan parameters. It is obvious in Figure 4. that according to the different materials, the distribution of CNR values was similar independently on the NI, DRF, AF or mAs settings. The highest CNR was characteristic to the air (NI=2.8 NCR=514), and the lowest to the acrylic (CT2, CNR=3.68). It can be seen that the CNR values mostly depend on the HU values of the examined material. The HU...

The image quality of different vendor’s CT scanners can be compared and harmonized based on CNR values and utilizing phantom scans. In this study, we only focused on head CT investigations, other protocol types, such as lung, and torso also should be considered and analysed to reach even more general conclusions.

L. Egeresi; Debrecen/HU Author at Div. of Radiology, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Hungary L. Balkay; Debrecen/HU Author at Div. of Nuclear Medicine, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Hungary E. Balázs; Debrecen/HU - Author at University of Debrecen, Kenézy Gyula University Hospital, Department of Diagnostic Radiology, Hungary Zs. Dankó; Debrecen/HU - Author at University of Debrecen, Kenézy Gyula University Hospital, Department of Diagnostic Radiology, Hungary C. Sokvári; Debrecen/HU - Author at Div. of Radiology, Department...

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