Department of Radiology, Medical University of Innsbruck, Innsbruck, Austria.
Department of Imaging and Pathology, OMFS-IMPATH Research Group, KU Leuven and Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.
Dentomaxillofac Radiol. 2023 Feb;52(3):20220387. doi: 10.1259/dmfr.20220387. Epub 2023 Jan 23.
As-low-as-diagnostically-acceptable (ALADA) doses are substantially lower than current diagnostic reference levels. To improve dose management, a reference quality approach was tested in which phantom quality metrics of a clinical ALADA dose reference protocol were used to benchmark potential ALADA dose protocols for various scanner models.
Spatial resolution, contrast resolution, contrast-to-noise ratio (CNR) and subjective noise and sharpness were evaluated for a clinical ALADA dose reference protocol at 80 kV and 40 mA (CTDIvol 2.66 mGy) and compared with test protocols of two CT scanners at 100 kV and 35 mA (3.08-3.44 mGy), 80 kV and 54-61 mA (2.65 mGy), 80 kV and 40 mA (1.73-1.92 mGy), and 80 kV and 21-23 mA (1.00-1.03 mGy) using different kernels, filtered backprojection and iterative reconstructions. The test protocols with the lowest dose showing quality metrics non-inferior to the reference protocol were verified in a cadaver study by determining the diagnostic accuracy of detection of maxillofacial fractures and CNR of the optical nerve and rectus inferior muscle.
36 different image series were analysed in the phantom study. Based on the phantom quality metrics, potential ALADA dose protocols at 1.73-1.92 mGy were selected. Compared with the reference images, the selected protocols showed non-inferiority in the detection and classification of maxillofacial fractures and non-inferior CNR of orbital soft tissues in the cadaver study.
Reference quality metrics from clinical ALADA dose protocols may be used to guide selection of potential ALADA dose protocols of different CT scanners.
尽可能低的诊断可接受剂量（ALADA）明显低于当前的诊断参考水平。为了改善剂量管理，测试了一种参考质量方法，该方法使用临床 ALADA 剂量参考方案的体模质量指标来对各种扫描仪模型的潜在 ALADA 剂量方案进行基准测试。
在 80kV 和 40mA（CTDIvol 2.66mGy）下评估临床 ALADA 剂量参考方案的空间分辨率、对比分辨率、对比噪声比（CNR）以及主观噪声和锐度，并与两台 CT 扫描仪的测试方案进行比较：100kV 和 35mA（3.08-3.44mGy）、80kV 和 54-61mA（2.65mGy）、80kV 和 40mA（1.73-1.92mGy）以及 80kV 和 21-23mA（1.00-1.03mGy），使用不同的内核、滤波反投影和迭代重建。在尸体研究中，通过确定检测颌面骨折和视神经及下直肌 CNR 的诊断准确性，验证了使用最低剂量且质量指标不劣于参考方案的测试方案。
在体模研究中分析了 36 个不同的图像系列。基于体模质量指标，选择了 1.73-1.92mGy 的潜在 ALADA 剂量方案。与参考图像相比，所选方案在尸体研究中显示出在颌面骨折的检测和分类以及眼眶软组织的 CNR 方面具有非劣效性。
来自临床 ALADA 剂量方案的参考质量指标可用于指导不同 CT 扫描仪的潜在 ALADA 剂量方案的选择。
