Svalkvist Angelica, Båth Magnus
Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden.
Radiat Prot Dosimetry. 2010 Apr-May;139(1-3):57-61. doi: 10.1093/rpd/ncq058. Epub 2010 Feb 22.
Adding noise to clinical radiographs to simulate dose reduction can be used to investigate the relationship between dose level and clinical image quality without exposing patients to additional radiation. The purpose of the present paper was to examine the benefits of using a method that accounts for detective quantum efficiency (DQE) variations that may occur in different dose ranges in the simulated dose reduction process. A method initially intended for simulated dose reduction in tomosynthesis was applied to extremely low-dose posterioanterior radiographs of an anthropomorphic chest phantom, selected from a group of projection images included in a tomosynthesis examination and compared with a previous method that do not account for DQE variations. A comparison of images simulated to be collected at a lower dose level (73 % of the original dose level) and images actually collected at this lower dose level revealed that the error in the integrated normalised noise power spectrum was smaller than 4 % for the method that accounts for DQE variations in the simulated dose reduction, whereas the error was larger than 20 % for the previous method. This indicates that an increased validity in dose reduction simulation of digital radiographic systems is obtained with a method accounting for DQE variations.
在临床X光片中添加噪声以模拟剂量降低，可用于研究剂量水平与临床图像质量之间的关系，而无需让患者接受额外辐射。本文的目的是检验使用一种考虑在模拟剂量降低过程中不同剂量范围内可能出现的探测量子效率（DQE）变化的方法的益处。一种最初用于模拟断层合成中剂量降低的方法被应用于一个拟人化胸部模型的极低剂量后前位X光片，这些X光片选自一组断层合成检查中的投影图像，并与之前一种不考虑DQE变化的方法进行比较。对模拟在较低剂量水平（原始剂量水平的73%）采集的图像和实际在该较低剂量水平采集的图像进行比较后发现，对于在模拟剂量降低中考虑DQE变化的方法，积分归一化噪声功率谱的误差小于4%，而对于之前的方法，误差大于20%。这表明，采用一种考虑DQE变化的方法可提高数字射线照相系统剂量降低模拟的有效性。
