Martinez-Cruz S, Manson-Hing L R
J Am Dent Assoc. 1987 May;114(5):639-42. doi: 10.14219/jada.archive.1987.0139.
Panoramic focal trough dimensions affect both the number of patient structures seen in radiographs and the margin of error possible when positioning a patient to take a radiograph. This study compares the dimensions, or size, and position, or form, of the focal troughs of four machines by resolution measurements. There is a continued need for technicians to position the patient's anterior teeth accurately in the zones of sharpness of these machines, but the widths of the sharpness zones show an increase in dimensions over older panoramic machines.
全景聚焦槽的尺寸既会影响X光片中可见的患者结构数量，也会影响患者定位拍摄X光片时可能出现的误差范围。本研究通过分辨率测量比较了四台机器聚焦槽的尺寸（或大小）和位置（或形态）。技术人员仍需要将患者的前牙准确地定位在这些机器的清晰区域，但与老式全景机器相比，这些清晰区域的宽度有所增加。
