Department of Endodontics, Center for Advanced Dental Education, Saint Louis University, Saint Louis, Missouri.
Department of Endodontics, Center for Advanced Dental Education, Saint Louis University, Saint Louis, Missouri.
J Endod. 2024 Jul;50(7):966-975. doi: 10.1016/j.joen.2024.02.006. Epub 2024 Feb 19.
Diagnostic reference levels (DRLs) are intended to improve patient safety and ensure that patient ionizing radiation doses are as low as reasonably achievable. The purpose of this dosimetry study was to establish regional DRL levels for cone-beam computed tomography (CBCT) imaging for specialty endodontics. Another aim was to compare phantom-measured ionizing radiation dose index 1 (DI1) index doses to the manufacturer-provided dose area product (DAP) radiation output values for each of the CBCT machines studied, to ascertain their degree of correlation. DAP refers to the dose area product, a measure of radiation dose monitoring which represents the dose within the beam times the area within the beam at that position.
A thimble ionization chamber and polymethyl methacrylate phantom were used to obtain DI1 values using the SEDENTEXTCT method from 21 different CBCT units. DRLs were calculated based on the 75th percentile (third quartile) of the median output values.
The proposed DRL from the CBCT units surveyed has a DAP value of 838 mGy cm and a DI1 value of 3.924 mGy. DAP versus DI1 values of 500.6 mGy cm versus 2.006 mGy, and 838 mGy cm versus 3.906 mGy represented the third quartile of the median values for the 4-cm × 4-cm and 5-cm × 5-cm field of views (FOVs), respectively.
The DI1 and DAP values strongly correlated when 3 outlier CBCT machines (J Morita Veraview X800) using a novel 360° (full rotation) acquisition mode were excluded. The importance of selectable exposure parameters as directly related to ionizing radiation output is illustrated among the CBCT units surveyed. Although the actual FOV that is selected is ultimately dictated by the specific clinical requirements, a 4-cm × 4-cm FOV is recommended for specialist endodontics practice, whenever clinically practical, based on the decreased ionizing radiation output, as compared to that from a 5-cm × 5-cm FOV.
诊断参考水平（DRL）旨在提高患者安全性并确保患者的电离辐射剂量尽可能低。本剂量学研究的目的是为专业牙髓学的锥形束计算机断层扫描（CBCT）成像建立区域 DRL 水平。另一个目的是比较每个研究的 CBCT 机的模体测量的电离辐射剂量指数 1（DI1）指数剂量与制造商提供的剂量面积乘积（DAP）辐射输出值，以确定它们的相关性程度。DAP 是指剂量面积乘积，是辐射剂量监测的一种度量，它表示束内的剂量乘以该位置的束内面积。
使用 SEDENTEXTCT 方法，通过 21 个不同的 CBCT 设备获得了 DI1 值，使用的是 thimble 电离室和聚甲基丙烯酸甲酯（PMMA）体模。根据中位数输出值的第 75 百分位数（第三四分位数）计算 DRL。
在所调查的 CBCT 设备中，建议的 DRL 的 DAP 值为 838 mGy cm，DI1 值为 3.924 mGy。DAP 与 DI1 值分别为 500.6 mGy cm 和 2.006 mGy，838 mGy cm 和 3.906 mGy 分别代表 4 cm×4 cm 和 5 cm×5 cm 视野（FOV）的中位数的第三四分位数。
当排除使用新颖的 360°（全旋转）采集模式的 3 台异常 CBCT 机（J Morita Veraview X800）时，DI1 和 DAP 值具有很强的相关性。在所调查的 CBCT 设备中，说明了可选择的曝光参数与电离辐射输出直接相关的重要性。尽管最终由具体的临床需求决定选择的实际 FOV，但基于与 5 cm×5 cm FOV 相比，电离辐射输出减少，建议在专业牙髓学实践中，只要在临床实践中可行，就选择 4 cm×4 cm FOV。
