School of Health Sciences, University of Salford, Salford M6 6PU, United Kingdom.
School of Health Sciences, University of Salford, Salford M6 6PU, United Kingdom.
Phys Med. 2019 Jan;57:65-71. doi: 10.1016/j.ejmp.2018.12.009. Epub 2018 Dec 25.
To evaluate the influence of being overweight on image quality (IQ), radiation dose and acquisition parameters when undertaking adult chest X-ray (CXR) examinations using routine acquisition protocols.
The Lungman chest phantom, with and without chest plates, was used to simulate the chest region for larger size and average adult patients, respectively. Radiographic acquisitions were conducted using 17 X-ray machines located in eight hospitals using their routine clinical protocols. IQ was assessed using relative visual grading analysis (VGA) and 2 alternative forced choice (2AFC) by six observers. Incident air kerma (IAK) was measured using a solid-state dosimeter.
IQ mean (range) scores between the hospitals were 16.2 (12.0-21.3) with a 56.0% difference and 20.9 (14.1-23.6) with a 50.2% difference for the standard and larger size phantoms, respectively. IAK mean (range) scores 63 µGy (19-136 µGy) with a 150% difference and 159 µGy (27-384 µGy) with a 173% difference for the standard and larger size phantoms, respectively. The chest plates had a significant negative impact on IQ (P = 0.001) and lead to an increased in IAK by approximately 50%.
Visual measures of IQ and IAK showed large differences between hospitals for standard and larger phantom sizes; differences within the hospitals was lower. Overall, Lungman with chest plates was found to degrade IQ and increase radiation dose by a factor of two. Further optimisation is required especially for the larger sized patient's imaging protocols for all eight hospitals.
评估在使用常规采集方案进行成人胸部 X 射线（CXR）检查时，超重对图像质量（IQ）、辐射剂量和采集参数的影响。
使用 Lungman 胸部体模，分别模拟较大体型和普通成年患者的胸部区域。使用位于 8 家医院的 17 台 X 射线机，根据其常规临床方案进行放射摄影采集。使用相对视觉分级分析（VGA）和 6 位观察者的两种替代强迫选择（2AFC）评估 IQ。使用固态剂量计测量入射空气比释动能（IAK）。
医院之间的 IQ 均值（范围）评分分别为 16.2（12.0-21.3），差异为 56.0%，20.9（14.1-23.6），差异为 50.2%，分别为标准和较大体型体模。IAK 均值（范围）评分分别为 63µGy（19-136µGy），差异为 150%，159µGy（27-384µGy），差异为 173%，分别为标准和较大体型体模。胸部板对 IQ 有显著负面影响（P=0.001），并导致 IAK 增加约 50%。
标准和较大体型体模的 IQ 和 IAK 的视觉测量结果在医院之间存在较大差异；医院内部的差异较小。总体而言，Lungman 带胸部板会降低 IQ 并将辐射剂量增加一倍。需要进一步优化，特别是针对所有 8 家医院的较大体型患者的成像方案。
