Department of Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan.
Department of Radiological Technology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
J Radiol Prot. 2023 Sep 22;43(3). doi: 10.1088/1361-6498/acf868.
Children are sensitive to radiation; therefore, it is necessary to reduce radiation dose as much as possible in pediatric patients. In addition, it is crucial to investigate the optimal imaging conditions as they considerably affect the radiation dose. In this study, we investigated the effect of different imaging conditions on image quality and optimized the imaging conditions for dental cone-beam computed tomography (CBCT) examinations to diagnose ectopic eruptions and impacted teeth in children. To achieve our aims, we evaluated radiation doses and subjective and objective image quality. The CBCT scans were performed using 3D Accuitomo F17. All combinations of a tube voltage (90 kV), tube currents (1, 2, 3 mA), fields of view (FOVs) (4 × 4, 6 × 6 cm), and rotation angles (360°, 180°) were used. Dose-area product values were measured. SedentexCT IQ cylindrical phantom was used to physically evaluate the image quality. We used the modulation transfer function as an index of resolution, the noise power spectrum as an index of noise characteristics, and the system performance function as an overall evaluation index of the image. Five dentists visually evaluated the images from the head-neck phantom. The results showed that the image quality tended to worsen, and scores for visual evaluation decreased as tube currents, FOVs and rotation angles decreased. In particular, image noise negatively affected the delineation of the periodontal ligament space. The optimal imaging conditions were 90 kV, 2 mA, 4 × 4 cm FOV and 180° rotation. These results suggest that CBCT radiation doses can be significantly reduced by optimizing the imaging conditions.
儿童对辐射敏感；因此，有必要尽量减少儿科患者的辐射剂量。此外，研究最佳成像条件至关重要，因为它们会极大地影响辐射剂量。在这项研究中，我们研究了不同成像条件对图像质量的影响，并优化了口腔锥形束 CT（CBCT）检查的成像条件，以诊断儿童的异位萌出和阻生牙。为了达到我们的目的，我们评估了辐射剂量以及主观和客观的图像质量。使用 3D Accuitomo F17 进行 CBCT 扫描。使用了管电压（90kV）、管电流（1、2、3mA）、视野（FOV）（4×4、6×6cm）和旋转角度（360°、180°）的所有组合。测量了剂量面积产品值。SedentexCT IQ 圆柱形体模用于物理评估图像质量。我们使用调制传递函数作为分辨率指标，噪声功率谱作为噪声特性指标，系统性能函数作为图像的整体评估指标。五名牙医从头颈部体模评估图像。结果表明，随着管电流、FOV 和旋转角度的降低，图像质量趋于恶化，视觉评估得分降低。特别是，图像噪声会对牙周膜间隙的描绘产生负面影响。最佳成像条件为 90kV、2mA、4×4cm FOV 和 180°旋转。这些结果表明，通过优化成像条件可以显著降低 CBCT 辐射剂量。
