Shrout M K, Hildebolt C F, Vannier M W
Department of Oral Diagnosis and Patient Services, Medical College of Georgia, School of Dentistry, Augusta.
Dentomaxillofac Radiol. 1993 Feb;22(1):33-7. doi: 10.1259/dmfr.22.1.8508940.
Errors in X-ray beam alignment account for many of the exposure errors in bitewing radiography. A new method for measuring these alignment errors is described. The alignment accuracy of two different models of inexpensive plastic positioning devices, used for bitewing radiography, were quantified and compared. The technique involves documenting the alignment of an 'ideal' reference radiograph and successive exposures. It permits calculation of X-ray beam-film alignment errors in all subsequent radiographs using the 'ideal' reference. Bitewing radiographs were taken on 61 patients and 19 of these were re-radiographed at 6-month intervals over a 2-year period, providing a total of 156 radiographs for the study. Horizontal and vertical angular deviations were measured and total alignment errors calculated for each radiograph. The average angular alignment error was less than 2 degrees total angular error (1.3-2.4 degrees, 95% confidence intervals). It is concluded that these devices can be used when X-ray beam-film alignment error below 2.5 degrees is acceptable.
X线投照束校准误差是咬合翼片X线摄影中许多曝光误差的原因。本文描述了一种测量这些校准误差的新方法。对两种用于咬合翼片X线摄影的不同型号廉价塑料定位装置的校准精度进行了量化和比较。该技术包括记录一张“理想”参考X线片和后续多次曝光的校准情况。它允许使用“理想”参考片计算所有后续X线片中X线投照束与胶片的校准误差。对61例患者进行了咬合翼片X线摄影，其中19例在2年期间每隔6个月重新进行X线摄影，共获得156张X线片用于研究。测量每张X线片的水平和垂直角度偏差，并计算总校准误差。平均角度校准误差小于2度总角度误差（1.3 - 2.4度，95%置信区间）。得出的结论是，当X线投照束与胶片的校准误差低于2.5度时，可以使用这些装置。
