Farman A G, Farman T T
Division of Radiology and Imaging Sciences, University of Louisville, Louisville Health Sciences Center, KY.
J Digit Imaging. 1998 Aug;11(3 Suppl 1):166-8. doi: 10.1007/BF03168293.
Panoramic radiography using a slit beam and film/screen receptor is standard for the emergency room evaluation of mandibular fractures and also in dentistry. This study compared the spatial resolution, area distortion factors, and the dosage considerations for a panoramic system where standard film/screen and a charge-coupled device were alternatively employed as the image receptor. Resolution and image contours were determined using a lead resolution grid positioned at selected beam projection angulations. Exposure measurements were carried out using a RANDO average man phantom and a 3 cc beryllium-windowed ionization chamber. The maximum spatial resolution with film approached 5 lp mm-1 whereas with the CCD the maximum resolution was just above 4 lp mm-1. Consequently, the image layer was reduced slightly in width when using the CCD receptor. The use of the CCD resulted in skin exposure reduction exceeding 70%.
使用狭缝光束和胶片/增感屏接收器的全景X线摄影术是急诊室评估下颌骨骨折以及牙科领域的标准方法。本研究比较了分别使用标准胶片/增感屏和电荷耦合器件作为图像接收器的全景系统的空间分辨率、面积失真因素和剂量考量。通过将铅分辨率格栅置于选定的光束投射角度来确定分辨率和图像轮廓。使用RANDO平均人体模型和一个3 cc铍窗电离室进行曝光测量。使用胶片时的最大空间分辨率接近5 lp mm-1，而使用电荷耦合器件时的最大分辨率略高于4 lp mm-1。因此，使用电荷耦合器件接收器时图像层的宽度略有减小。使用电荷耦合器件可使皮肤暴露减少超过70%。
