Horizontal X-ray Beam Direction in Panoramic Radiography

• Published in: Shika Hoshasen Vol. 52; no. 1; pp. 9 - 14
• Main Authors: Yokoi, Midori, Katsumata, Akitoshi, Naitoh, Munetaka, Goto, Kenichi, Hirukawa, Akiko, Matsuo, Ayae, Okumura, Shinji, Ariji, Eiichiro
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society for Oral and Maxillofacial Radiology 2012
• Subjects: Orthoradial projection; Panoramic radiography; Tomosynthesis technique
• ISSN: 0389-9705; 2185-6311
• DOI: 10.11242/dentalradiology.52.9

Panoramic radiography is one of the most frequently used radiological techniques in dentistry for the detection of dental caries and periodontal diseases. However, it is generally accepted that marked overlapping of the approximal surfaces of the teeth occurs frequently, making interpretation of caries and/or marginal bone loss difficult. Several methods have been proposed to overcome this problem. One is the improved orthoradial panoramic projection program (Veraview series, Morita, Japan), another is panoramic layer reconstruction based on the tomosynthesis method (PanoACT 1000, Axion, Japan). Therefore, we evaluated the deviation between the projection angle of the X-ray beam and the interproximal surfaces of the teeth in the dental arch by means of a special phantom. The phantom represented the optimal direction of the beam of radiation that is perpendicular to the average dental arch. As a result, in every panoramic image, the projection angle of the X-ray beam deviated medially from the optimal direction. In the conventional projection mode, the direction of the X-ray beam deviated from 25 degrees to 30 degrees in the premolars and the first molar region. The discrepancy in these regions was decreased from 10 degrees to 20 degrees in both improved panoramic projections.To achieve an ideal orthoradial projection for the dental arch, further improvements in imaging techniques are needed.