Determination of the resolution of a digital system for panoramic radiography based on CCD technology.
OBJECTIVE
To determine Line Spread Functions (LSFs) and Modulation Transfer Functions (MTFs) for a digital system for panoramic radiography: the Dimax I (Planmeca Oy, Helsinki, Finland) based on Charge-Coupled Device (CCD) technology.


METHODS
A test object was specially designed having a gold foil positioned vertically. Images of the gold foil created edge functions that were used to determine LSFs and MTFs. The design of the test object made it possible to move the gold foil forward and backward relative to the central plane of the image layer by means of a micrometer screw. The experiment was carried out for different object depths in 5 different regions: the anterior, the canine, the premolar, the molar, and the TMJ regions. LSFs and MTFs were calculated using specially designed software.


RESULTS
The results are presented graphically. LSFs and MTFs for the central plane were essentially the same for all regions. The MTFs for different object depths in the 5 investigated regions exhibited typical characteristics of MTFs for panoramic radiography with the exception for the functions for the molar region.


CONCLUSIONS
The present findings indicate that the resolution of the Dimax I CCD system is comparable to that of film-based panoramic radiography.
Mastoris
Mihalis
M
Department of Oral Diagnosis and Radiology, School of Dentistry, University of Athens, Ampelokipi, Greece. michaelmastoris@hotmail.com
Li
Gang
G
Welander
Ulf
U
McDavid
W D
WD
D001641:Bicuspid / Q000000981:diagnostic imaging; D003481:Cuspid / Q000000981:diagnostic imaging; D006047:Gold Alloys; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D008963:Molar / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement; D019252:Radiography, Dental, Digital; D011862:Radiography, Panoramic; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging; D014962:X-Ray Film
D006047:Gold Alloys