[Examination of incident angle for photography of axial projection of zygomatic arch].

In axial zygomatic arch roentgenography, the radiographic angle is determined by taking account of the light field-projected image. However, this method is technically difficult and has poor reproducibility because the body target surface is uncertain at the time of positioning. Therefore, we obtained 3D-CT images from CT examinations of the facial or paranasal sinus, and we assessed the X-ray beam angle where the zygomatic arch is most clearly delineated in terms of sex and age by taking the acanthion-meatal line (France horizon) as the reference. The zygomatic arch was most clearly seen when the X-ray beam angle was perpendicular to the acanthion-meatal line. Excellent images were obtained, and reproducibility of the images was improved using the radiographic technique based on this result.