Helmrot Ebba, Alm Carlsson Gudrun
Department of Radiology, County Hospital Ryhov, SE-551 85 Jönköping, Sweden.
Radiat Prot Dosimetry. 2005;114(1-3):168-71. doi: 10.1093/rpd/nch502.
Patient dose audit is an important tool for quality control and it is important to have a well-defined and easy to use method for dose measurements. In dental radiology, the most commonly used dose parameters for the setting of diagnostic reference levels (DRLs) are the entrance surface air kerma (ESAK) for intraoral examinations and dose width product (DWP) for panoramic examinations. DWP is the air kerma at the front side of the secondary collimator integrated over the collimator width and an exposure cycle. ESAK or DWP is usually measured in the absence of the patient but with the same settings of tube voltage (kV), tube current (mA) and exposure time as with the patient present. Neither of these methods is easy to use, and, in addition, DWP is not a risk related quantity. A better method of monitoring patient dose would be to use a dose area product (DAP) meter for all types of dental examinations. In this study, measurements with a DAP meter are reported for intraoral and panoramic examinations. The DWP is also measured with a pencil ionisation chamber and the product of DWP and the height H (DWP x H) of the secondary collimator (measured using film) was compared to DAP. The results show that it is feasible to measure DAP using a DAP meter for both intraoral and panoramic examinations. The DAP is therefore recommended for the setting of DRLs.
患者剂量审核是质量控制的一项重要工具，拥有一种定义明确且易于使用的剂量测量方法很重要。在牙科放射学中，用于设定诊断参考水平（DRL）的最常用剂量参数，对于口腔内检查是入射表面空气比释动能（ESAK），对于全景检查是剂量宽度乘积（DWP）。DWP是在准直器宽度和一个曝光周期上对次级准直器前侧的空气比释动能进行积分。ESAK或DWP通常是在没有患者的情况下测量，但管电压（kV）、管电流（mA）和曝光时间的设置与有患者时相同。这些方法都不容易使用，此外，DWP不是一个与风险相关的量。一种更好的监测患者剂量的方法是在所有类型的牙科检查中使用剂量面积乘积（DAP）仪。在本研究中，报告了使用DAP仪对口腔内和全景检查的测量结果。还用一支铅笔电离室测量了DWP，并将DWP与次级准直器高度H（使用胶片测量）的乘积（DWP×H）与DAP进行了比较。结果表明，使用DAP仪测量口腔内和全景检查的DAP是可行的。因此，推荐使用DAP来设定DRL。
