Paiboon C, Manson-Hing L R
Oral Surg Oral Med Oral Pathol. 1985 Dec;60(6):670-6. doi: 10.1016/0030-4220(85)90374-3.
A resolution test pattern was used to determine the size, position, and centers of the focal troughs of four panoramic x-ray machines. The focal troughs were located at slightly different positions for each machine. The center of each focal trough produced varying degrees of sharpness. The average widths of the focal troughs were not greatly different between machines.