Impact of Chest CT Positioning Deviation on Radiation Dose and Image Quality:A Population-Based Study
10.3969/j.issn.1005-5185.2025.07.017
- VernacularTitle:胸部CT摆位偏离对辐射剂量与图像质量的影响:一项基于人群数据的研究
- Author:
Shiyi XIANG
1
;
Xinhong WANG
Author Information
1. 浙江中医药大学第一临床医学院,浙江 杭州 310009
- Publication Type:Journal Article
- Keywords:
Tomography,X-ray computed;
Radiation dosage;
Localization;
Image quality;
Chest
- From:
Chinese Journal of Medical Imaging
2025;33(7):780-784
- CountryChina
- Language:Chinese
-
Abstract:
Purpose To investigate the impact of patient positioning deviation on CT image quality and radiation dose in chest CT scans.Materials and Methods A retrospective analysis was conducted on all patients who underwent chest high-resolution CT plain scans from January 22 to 26,2024,at the Second Affiliated Hospital,Zhejiang University School of Medicine.The distance between the gantry center and patient center was measured.Patients were divided into three groups based on the magnitude of deviation from the isocenter:negative deviation group,isocenter group and positive deviation group.Compared the signal to noise ratio(SNR),CT dose index volume(CTDIvol),dose length product(DLP)and SNR/CTDI distribution among the three patient groups.Results Among the 965 patients studied,29.95%(289 cases)were accurately positioned,while 70.05%(676 cases)deviated from the center.The frequency of positive deviation(31.81%,307/965)was lower than that of negative deviation(38.24%,369/965).Compared with the isocenter group,patients in the negative deviation group received higher CTDIvol and DLP but superior SNR,while those in the positive deviation group received lower CTDIvol and DLP with inferior SNR(H=213.783,187.595,59.247,all P<0.05).The SNR/CTDI ratio in the isocenter group 0.84(0.50)was significantly higher than that in the negative deviation group 0.72(0.54)and the positive deviation group 0.71(0.38)(H=13.257,P<0.05).There was a significant association between gender and deviation direction.Patients with higher body weight and taller stature,particularly male patients,demonstrated negative deviation,while those with lower body weight and shorter stature tended to positive deviation.Conclusion Accurate positioning in chest CT scans can ensure diagnostic accuracy while minimizing radiation exposure and achieving the best image quality-to-radiation dose ratio.However,as a population-based preliminary study,the findings should be complemented by phantom experiments to further validate the correlation between anthropometric parameters and positional deviations in clinical CT practice.
