Department of Dentistry, Oral Pathology and Maxillofacial Surgery, Katholieke Universiteit Leuven, Leuven, Belgium.
Forensic Sci Int. 2010 Jan 30;194(1-3):20-7. doi: 10.1016/j.forsciint.2009.09.024. Epub 2009 Nov 12.
Recently, different portable hand-held and battery-powered dental X-ray units have become available. Especially for forensic odontological purposes, they offer diverse advantages such as for use in disaster areas and crime-scene locations as also in autopsy rooms and mortuaries. For any application, the most important feature of these hand-held devices is the delivered image quality. The aim of this study is to evaluate the radiographic image quality acquired by two portable X-ray devices in combination with two types of image receptors and to compare the findings with the image quality of a standard intra-oral X-ray device. Eleven samples consisting of eight teeth, two dry skeletal specimens and one formalin-fixed mandible part were mounted on blocks for standardised (re)positioning. Radiological images were acquired with two hand-held (AnyRay 60 kVp, 0.02-4.00 mAs and NOMAD 60 kVp, 0.023-2.277 mAs) and one wall-mounted (MinRay 60/70 kVp 0.14-22.4 mAs) X-ray device combined with two image receptor systems (VistaScan phosphor storage plate (PSP) and SIGMA M CMOS Active Pixel technology sensor). The effect of X-ray source-to-object distance (SOD) was checked at 20 cm in conjunction with object to image receptor distances (OIDs) of 0.8 and 2.5 cm. For each parameter setup, the exposure times were run from low till high. An expert consent statement was achieved by agreement of four expert observers selecting the optimal images based on a developed four point quality rating system. Next, a selection of the images was assembled in a set of 198 observation screens and scored by seven observers. The observation screens were designed to compare observer scores, relations between devices, receptors and OIDs and images obtained from the different devices at equal exposure levels (mAs). All results were statistically analysed. Radiological image quality was significantly higher for phosphor plate compared with the CMOS digital receptor system (p<0.0001). Furthermore, a significantly superior image quality was obtained for OID=0.8 than for OID=2.5 (p=0.039). A significant difference in image quality between the three devices was also established (p=0.02). The present study demonstrated the feasibility of portable X-ray systems for forensic odontological applications based on rendering optimal image quality, provided an in vitro guideline of optimal parameter settings and offered a radiological image database usable in further research.
最近，不同的便携式手持和电池供电的牙科 X 射线设备已经面世。特别是对于法医牙科学目的，它们具有多种优势，例如在灾区和犯罪现场以及解剖室和太平间使用。对于任何应用，这些手持设备最重要的特点是所提供的图像质量。本研究的目的是评估两种便携式 X 射线设备与两种类型的图像接收器组合获得的射线照相图像质量，并将结果与标准口腔内 X 射线设备的图像质量进行比较。十一组样本由八颗牙齿、两个干燥的骨骼标本和一个福尔马林固定的下颌部分组成，安装在用于标准化（重新）定位的块上。使用两种手持式（AnyRay 60 kVp，0.02-4.00 mAs 和 NOMAD 60 kVp，0.023-2.277 mAs）和一种壁装式（MinRay 60/70 kVp 0.14-22.4 mAs）X 射线设备以及两种图像接收器系统（VistaScan 磷光存储板（PSP）和 SIGMA M CMOS 有源像素技术传感器）获取射线照相图像。检查了 X 射线源到物体的距离（SOD）的影响，同时在 0.8 和 2.5 cm 的物体到图像接收器距离（OID）处结合使用。对于每个参数设置，曝光时间从低到高运行。四名专家观察员通过达成协议，选择基于开发的四点质量评分系统的最佳图像来实现专家同意声明。接下来，选择一些图像组装在一组 198 个观察屏幕中，并由七名观察员进行评分。观察屏幕旨在比较观察者评分、设备、接收器和 OID 之间的关系以及从不同设备在相等曝光水平（mAs）下获得的图像。所有结果均进行了统计学分析。与 CMOS 数字接收器系统相比，磷光板的射线照相图像质量显著更高（p<0.0001）。此外，OID=0.8 比 OID=2.5 获得的图像质量显著更好（p=0.039）。还确定了三种设备之间图像质量的显著差异（p=0.02）。本研究证明了基于提供最佳图像质量的便携式 X 射线系统在法医牙科学应用中的可行性，提供了最佳参数设置的体外指南，并提供了可在进一步研究中使用的射线照相图像数据库。
