| Qi Hui,Cui Dingye,Li Wei.Preliminary study on the effects of different scanning methods on phantom image quality in a wide-body detector CT scanner[J].Chinese Journal of Radiological Medicine and Protection,2024,44(7):622-627 |
| Preliminary study on the effects of different scanning methods on phantom image quality in a wide-body detector CT scanner |
| Received:October 18, 2023 |
| DOI：10.3760/cma.j.cn112271-20231018-00125 |
| KeyWords:Detector width Scanning mode Spatial resolution Noise |
| FundProject:山东省科技发展计划(2014GSF118091);山东省医药卫生发展计划(2017WS715) |
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| Abstract:: |
| Objective To explore the effects of different scan modes and detector widths on image quality and radiation dose in a wide-body detector CT scanner using phantoms. Methods A 320-row CT scanner was used to scan Catphan500 CTP404 and CTP486 modules under different scan modes, during which each module was positioned in the center of the scanning field. On the axial scan, the detector collimating width options of 80, 120, 140, and 160 mm were applied successively; on the helical scan, the options of 40 and 80 mm were applied. Tube currents of 240 and 100 mAs were used for both scan modes. The imQuest software, which measures spatial resolution by task-based transfer function (TTF) and noise by noise power spectrum (NPS), was used for objective evaluation, and feature data and CTDIvol values of images were recorded. Results Scan modes had a significant effect on the spatial resolution and noise of images. For spatial resolution, the TTF curve on the axial scan shifted slightly to the right compared with that on the helical scan, suggesting the association between axial scan and higher spatial resolution; for noise, the NPS peak frequency and average spatial frequency revealed a similar noise texture with the two scan modes, but the noise value and the identical area under the NPS curve suggested that axial scan was less noisy. It had 14% less noise, 26% less area under the curve, better image quality, and about 13% less radiation dose on axial scan than those on spiral scan. The detector collimating width had no significant effect on high contrast resolution and noise, but CTDIvol decreased with its increase, and CTDIvol reduced by 9% when it was doubled on the axial scan. Conclusions Different scanning method have certain effects on image quality and radiation dose, especially scan modes. In clinical practice, it is required to choose an appropriate scanning method based on the scanning sites and diagnostic requirements. |
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