The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 30, 1993
Filed:
May. 04, 1992
Arto Virta, Helsinki, FI;
Planmeca Oy, , FI;
Abstract
The invention concerns a method and apparatus for narrow-beam tomography in which a narrow x-ray beam (X) emitted from an x-ray source (12) is aimed to pass through the object area to be radiographed onto a transferrable x-ray film (F). The object area to be imaged in the patient (P) is kept stationary in a certain preset position, while the x-ray source (12) is rotated about a virtual axis of rotation (R.sub.0) and the film cassette (14) is simultaneously transferred. In the first imaging mode for the panoramic radiography of the dental arch (L), the patient (P) is supported by patient positioning means (20 . . . 30) so that the sharply imaging plane is located between the virtual axis of rotation and the film plane. In addition to said first imaging mode, the panoramic x-ray apparatus is adjustable for a specific mandibular joint imaging mode in which the patient is supported in the panoramic x-ray apparatus using said patient positioning means (20 . . . 30). The speeds (v.sub.R, v.sub.1) of the rotating motor (31) and the film transfer motor (32) in a frame part (15) supporting the x-ray source (12) and the film cassette (14) are varied, or alternatively, the profiles of said speeds are set so that the shape of the sharply-imaging layers (P.sub.1 -P.sub.1,P.sub.2 -P.sub.2) is appropriately contoured so as to make the mandibular joints (K) coincide with the imaged layer irrespective of the position of the patient (P) in the medial-sagittal plane (MS).