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

الملخص EN

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 in 26 patients each with both screen–film and CCD systems.

The images were obtained with TRATO 2000, CE by VILLA SISTEMI MEDICALIS–ITALY with regular intensifying screen type Kodak Lanex and 6 x 12 inch screen type film used for film–based projection, while Dimax3 digital system pan/ceph, PLANMECA, Helsinki, Finland with CCD X–ray image sensor (the size of the panoramic sensor was 15 x 30 cm and the resolution of the panoramic image was around 230 dpi, used for digital projection.

Both X–ray machines were operated at range of 70–80 kV and 10–12 mA, according to the patient age.

Altogether, the digital images files were displayed on 17 inch monitor, brightness and contrast were fixed and no enhancement was made before the digital images files were saved.

While the film–based images after processing were viewed on the viewer box.

Image quality was assessed by rating the visibility of five anatomical landmarks commonly found on panoramic radiographs: The superior and inferior cortex of the mandibular canal, the superior and inferior margin of the mental foramen, the lower and anterior border of the maxillary sinus, the lower border of the mandible, 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 should be improved), or unacceptable (image not of diagnostic quality).

Each image was then given an overall evaluation rating of good, acceptable, or unacceptable.

Results: The data collected from the evaluation of the digital and film–based images by the three examiners, were analyzed by 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 three examiners.

The difference between the film–based and the digital images systems was not statistically significant (P>0.05).

Conclusions: It was concluded that digital panoramic radiographs are equivalent to film–based images for the five anatomical landmarks.