title: Effects of dose reduction on multi-detector computed tomographic images in evaluating the maxilla and mandible for pre-surgical implant planning: a cadaveric study.
abstract: OBJECTIVE
  To assess effects of dose reduction on image quality in evaluating maxilla and mandible for pre-surgical implant planning using cadavers.
  
  
  METHODS
  Six cadavers were used for the study using multi-detector computed tomography (CT) operated at 120 kV and the variable tube current of 80, 40, 20 and 10 mA. A slice thickness of 0.625 mm and pitch 1 were used. Multi-planar images perpendicular and parallel to dentitions were created. The images were evaluated by five oral radiologists in terms of visibility of the anatomical landmarks including alveolar crest, mandibular canal, floors of the maxillary sinus and nasal cavity, contours/cortical layer of jaw bones and the details of trabecular bone. Observers were asked to determine the quality of the images in comparison with 80 mA images based on the criteria: excellent, good, fair or non-diagnostic. The average scores of all observers were calculated for each specimen in all exposure conditions.
  
  
  RESULTS
  The 40 mA images could visualize such landmarks and were evaluated to be same or almost equivalent in quality to the 80 mA images. Even the 20 mA images could be accepted just for diagnostic purpose for implant with substantial deterioration of the image quality. The 10 mA images may not be accepted because of the obscured contour caused by image noise.
  
  
  CONCLUSIONS
  Significant dose reduction by lowering mA can be utilized for pre-surgical implant planning in multi-detector CT.
authors.affiliation: Department of Radiology, Showa University School of Dentistry, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Koizumi
authors.forename: Jaideep
authors.initials: J
authors.lastname: Sur
authors.forename: Kenji
authors.initials: K
authors.lastname: Seki
authors.forename: Koh
authors.initials: K
authors.lastname: Nakajima
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sano
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Okano
mesh_terms: D002102:Cadaver; D003758:Dental Implantation, Endosseous; D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging*; D008437:Maxilla / Q000000981:diagnostic imaging*; D010347:Patient Care Planning; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods*