Lee Ki Baek, Kim Seong Min, Yoon Jong-Tae, Ahn Yura, Do Kyung-Hyun
Department of Radiologic Technology, Chungbuk Health & Science University, Cheongju 28150, Republic of Korea.
Department of Radiology, Asan Medical Center, Seoul 05505, Republic of Korea.
Eur J Radiol. 2025 Jul;188:112120. doi: 10.1016/j.ejrad.2025.112120. Epub 2025 Apr 17.
To propose a method to effectively reduce radiation dose while enhancing image quality in chest CT for patients unable to elevate their arms utilizing the air-gap technique.
Chest CT images were acquired in three positions: arms raised (control group, position A), arms lowered with the air-gap technique utilizing an in-house device (position B), and arms lowered without the device (position C). Data were categorized by body weight. Radiation dose was assessed using dose-length product (DLP) values, with quantitative analyses of image noise, contrast-to-noise ratio (CNR), and CNR-to-dose ratio (CNRDR). Qualitative assessment utilized a Likert scale.
Average DLP was 473.7 ± 142.9 mGy × cm in position C, with the lowest in position A at 267.3 ± 93.3 mGy × cm. Position B had a DLP of 317.2 ± 121.4 mGy × cm, 18.7 % higher than position A but 33.0 % lower than position C. In patients over 70 kg, all positions exceeded the thoracic CT diagnostic reference level (DRL) (324.2 mGy × cm). For those under 70 kg (i.e., <50 kg, 50-70 kg), position B showed lower DLPs compared to the above DRL. Quantitative analysis indicated that position B maintained image quality similar to position A, with CNRDR of 30.2 ± 11.1 versus 26.6 ± 10.9 in position A, showing marginal significance (p = 0.046). The qualitative evaluation indicated that position A had the highest rating at 4.96, followed by position B at 4.51, and position C at 3.47.
The air-gap device with lowered arms during chest CT for patients unable to elevate their arms can reduce radiation dose while maintaining image quality. A custom-designed device facilitates safe and efficient procedures, especially for patients with higher body weight.
提出一种方法，在胸部CT检查中，利用气隙技术，在提高无法抬起手臂的患者图像质量的同时有效降低辐射剂量。
在三个位置采集胸部CT图像：手臂抬起（对照组，位置A）、使用内部设备利用气隙技术手臂放下（位置B）、不使用设备手臂放下（位置C）。数据按体重分类。使用剂量长度乘积（DLP）值评估辐射剂量，并对图像噪声、对比度噪声比（CNR）和CNR与剂量比（CNRDR）进行定量分析。定性评估采用李克特量表。
位置C的平均DLP为473.7±142.9 mGy×cm，位置A最低，为267.3±93.3 mGy×cm。位置B的DLP为317.2±121.4 mGy×cm，比位置A高18.7%，但比位置C低33.0%。在体重超过70kg的患者中，所有位置均超过胸部CT诊断参考水平（DRL）（324.2 mGy×cm）。对于体重低于70kg（即<50kg、50-70kg）的患者，位置B的DLP低于上述DRL。定量分析表明，位置B保持的图像质量与位置A相似，位置B的CNRDR为30.2±11.1，位置A为26.6±10.9，显示出边缘显著性（p = 0.046）。定性评估表明，位置A的评分最高，为4.96，其次是位置B，为4.51，位置C为3.47。
对于无法抬起手臂的患者，在胸部CT检查时使用手臂放下的气隙设备可在保持图像质量的同时降低辐射剂量。定制设计的设备有助于安全高效地进行检查，特别是对于体重较高的患者。
