an evaluation of the film–based and digital panoramic radiographic quality

Aims: To compare the image quality of panoramic radiographs obtained with charge–coupled device(CCD) and screen–film systems. Materials and methods: True Panoramic radiographs were taken in26 patients each with both screen–film and CCD systems. The images were obtained with TRATO2000, CE by VILLA SISTEMI MEDICALIS–ITALY with regular intensifying screen typeKodak Lanex and 6 x 12 inch screen type film used for film–based projection, while Dimax3digital system pan/ceph, PLANMECA, Helsinki, Finland with CCD X–ray image sensor (thesize of the panoramic sensor was 15 x 30 cm and the resolution of the panoramic image was around230 dpi, used for digital projection. Both X–ray machines were operated at range of 70–80kV and 10–12 mA, according to the patient age. Altogether, the digital images files weredisplayed on 17 inch monitor, brightness and contrast were fixed and no enhancement wasmade before the digital images files were saved. While the film–based images after processingwere viewed on the viewer box. Image quality was assessed by rating the visibilityof five anatomical landmarks commonly found on panoramic radiographs: The superior andinferior cortex of the mandibular canal, the superior and inferior margin of the mentalforamen, the lower and anterior border of the maxillary sinus, the lower border of themandible, and the articular eminence. For each image, the given landmark was rated as good(image of excellent diagnostic quality), acceptable (image of diagnostic quality but shouldbe improved), or unacceptable (image not of diagnostic quality). Each image was then givenan overall evaluation rating of good, acceptable, or unacceptable. Results: The data collectedfrom the evaluation of the digital and film–based images by the three examiners, were analyzedby t–test. The image quality, as represented by each of the five anatomical landmarks,and the overall rating for each system were expressed as the mean scores of the threeexaminers. The difference between the film–based and the digital images systems was not statisticallysignificant (P>0.05). Conclusions: It was concluded that digital panoramic radiographs are equivalentto film–based images for the five anatomical landmarks.