Monsour P A, Mendoza A R
Department of Oral Biology and Oral Surgery, University of Queensland, St. Lucia, Australia.
Oral Surg Oral Med Oral Pathol. 1990 Jun;69(6):748-56. doi: 10.1016/0030-4220(90)90361-u.
Mapping of the ghost envelope for an Orth Oralix panoramic x-ray unit (Philips Medical Systems) was carried out with a lead sphere suspended at various locations around a dry mandible. The ghost envelope is a three-dimensional zone within which an object or anatomic structure must lie to produce a ghost image on panoramic radiographs. If the three-dimensional shape of the ghost envelope for a particular panoramic unit is known, information can be gained about the clinical location of objects appearing on radiographs produced with that machine. Objects outside the envelope will not result in ghost image formation. Objects within the envelope will result in characteristic ghost images depending on their position. This article analyzes ghost image characteristics in relation to object position and discusses the limitations of the method. A series of ready reference diagrams is provided, which may aid in the localization of soft tissue calcifications and foreign objects observed on panoramic radiographs.
使用一个铅球悬挂在干燥下颌骨周围的不同位置，对Orth Oralix全景X射线机（飞利浦医疗系统公司）的伪影包络进行了映射。伪影包络是一个三维区域，物体或解剖结构必须位于该区域内才能在全景X射线上产生伪影图像。如果已知特定全景设备的伪影包络的三维形状，就可以获得有关在该机器产生的X射线片上出现的物体的临床位置的信息。包络外的物体不会导致伪影图像形成。包络内的物体根据其位置会产生特征性的伪影图像。本文分析了与物体位置相关的伪影图像特征，并讨论了该方法的局限性。提供了一系列便于参考的图表，这可能有助于在全景X射线片上观察到的软组织钙化和异物的定位。
