Ludlow J B, Timothy R, Walker C, Hunter R, Benavides E, Samuelson D B, Scheske M J
1 North Carolina Oral Health Institute, Koury Oral Health Sciences, Chapel Hill, NC, USA.
Dentomaxillofac Radiol. 2015;44(1):20140197. doi: 10.1259/dmfr.20140197.
This article analyses dose measurement and effective dose estimation of dental CBCT examinations. Challenges to accurate calculation of dose are discussed and the use of dose-height product (DHP) as an alternative to dose-area product (DAP) is explored.
The English literature on effective dose was reviewed. Data from these studies together with additional data for nine CBCT units were analysed. Descriptive statistics, ANOVA and paired analysis are used to characterize the data.
PubMed and EMBASE searches yielded 519 and 743 publications, respectively, which were reduced to 20 following review. Reported adult effective doses for any protocol ranged from 46 to 1073 µSv for large fields of view (FOVs), 9-560 µSv for medium FOVs and 5-652 µSv for small FOVs. Child effective doses from any protocol ranged from 13 to 769 µSv for large or medium FOVs and 7-521 µSv for small FOVs. Effective doses from standard or default exposure protocols were available for 167 adult and 52 child exposures. Mean adult effective doses grouped by FOV size were 212 µSv (large), 177 µSv (medium) and 84 µSv (small). Mean child doses were 175 µSv (combined large and medium) and 103 µSv (small). Large differences were seen between different CBCT units. Additional low-dose and high-definition protocols available for many units extend the range of doses. DHP was found to reduce average absolute error for calculation of dose by 45% in comparison with DAP.
Large exposure ranges make CBCT doses difficult to generalize. Use of DHP as a metric for estimating effective dose warrants further investigation.
本文分析牙科CBCT检查的剂量测量和有效剂量估算。讨论了准确计算剂量所面临的挑战，并探讨了使用剂量-高度乘积（DHP）替代剂量-面积乘积（DAP）的情况。
回顾了关于有效剂量的英文文献。分析了这些研究的数据以及9台CBCT设备的额外数据。使用描述性统计、方差分析和配对分析来描述数据。
PubMed和EMBASE检索分别得到519篇和743篇出版物，经筛选后减少至20篇。对于任何扫描方案，报道的大视野（FOV）成人有效剂量范围为46至1073µSv，中视野为9至560µSv，小视野为5至652µSv。任何扫描方案的儿童有效剂量范围为大视野或中视野13至769µSv，小视野7至521µSv。有167例成人和52例儿童曝光的标准或默认曝光方案的有效剂量数据。按视野大小分组的成人平均有效剂量为大视野212µSv、中视野177µSv、小视野84µSv。儿童平均剂量为大视野和中视野合并175µSv，小视野103µSv。不同CBCT设备之间存在很大差异。许多设备提供的额外低剂量和高清方案扩大了剂量范围。与DAP相比，发现DHP可将剂量计算的平均绝对误差降低45%。
较大的曝光范围使得CBCT剂量难以一概而论。将DHP用作估算有效剂量的指标值得进一步研究。
