Bryndahl Fredrik, Legrell Per Erik, Eriksson Lars, Isberg Annika
Department of Odontology, Oral and Maxillofacial Radiology, Umeå University, Umeå, Sweden.
Angle Orthod. 2004 Oct;74(5):610-7. doi: 10.1043/0003-3219(2004)074<0610:TSIIOO>2.0.CO;2.
The aim of this study was to develop a method that optimizes the reliability of longitudinal radiographic evaluation of small and fast-growing animals, such as the rabbit. Because the use of conventional cephalometric methods, including superimposition of serial radiographs, is more problematic in small animals than in humans, two titanium-alloy screws were placed 10 mm apart in the sagittal crest of the parietal bone in 10 growing New Zealand white rabbits. The anterior screw served as holder for a steel pin that, in turn, secured the fixation of the rabbit's head to a specially designed cephalostat. A lateral cephalogram of each animal was exposed on four occasions at one-month intervals. Computer-aided superimpositions were made of all four cephalograms from each animal using the screws in the calvarium as reference structures. To evaluate the method, the superimpositions were repeated after three to eight weeks, and the superimposition reproducibility was calculated. From the results, it can be concluded that the method allows congruent positioning of the animal skull relative to the film-focus assembly at repeated radiographic examinations. Furthermore, it introduces readily identified reference structures in the animal skull that can be used at high-precision superimposition of serial radiographs.
本研究的目的是开发一种方法，以优化对小型快速生长动物（如兔子）进行纵向放射学评估的可靠性。由于在小动物中使用传统的头影测量方法（包括连续X线片的叠加）比在人类中更具问题，因此在10只生长中的新西兰白兔的顶骨矢状嵴上相距10毫米放置了两枚钛合金螺钉。前一枚螺钉用作钢针的固定点，而钢针又将兔子的头部固定到一个专门设计的头颅固定器上。每只动物每隔一个月进行四次头颅侧位片拍摄。使用颅骨中的螺钉作为参考结构，对每只动物的所有四张头颅侧位片进行计算机辅助叠加。为了评估该方法，在三到八周后重复叠加，并计算叠加的可重复性。从结果可以得出结论，该方法允许在重复的放射学检查中使动物颅骨相对于胶片-焦点组件进行一致的定位。此外，它在动物颅骨中引入了易于识别的参考结构，可用于连续X线片的高精度叠加。
