Charge-coupled device panoramic radiography: effect of beam energy on radiation exposure.
OBJECTIVE
To determine the consequences for entrance exposure of varying the beam energy and operating current for panoramic radiography using a charge-coupled device receptor.


METHODS
Images were made of a RANDO average man phantom (Alderson Research Laboratories, Stamford, CT) at kVcp settings of 60, 66, 70 and 80 and an mA of 2.0, 3.2, 6.4 and 10.0. The exposure cycle was set as recommended by the manufacturer at 17.6 s. Diagnostic image quality was rated by a panel of two oral and maxillofacial radiologists and one oral and maxillofacial pathologist. Entrance exposures were assessed using a 3 cc ionization chamber placed at the beam entry points while imaging the molar, premolar, and anterior teeth both using the DigiPan (Trophy Radiologie, Vincennes, France) CCD receptor and conventional T-Mat G film/Lanex Regular screens (Eastman Kodak, Rochester, NY, USA).


RESULTS
Acceptable image quality was attained with combinations of 60 kVcp and 3.2, 6.4 or 10 mA, 70 kVcp and 2.0, 3.2 or 6.4 mA; at 80 kVcp irrespective of the mA it was unacceptable. The maximum reduction in entrance dose was 77%, averaged over the three sites, at 70 kVcp and 2 mA.


CONCLUSIONS
The DigiPan receptor produces satisfactory images with saving in entry exposure saving of approximately 70% when compared with a conventional film/rare earth screen combination.
Farman
T T
TT
School of Dentistry, University of Louisville, Kentucky 40292, USA.
Farman
A G
AG
Kelly
M S
MS
Firriolo
F J
FJ
Yancey
J M
JM
Stewart
A V
AV
D001641:Bicuspid / Q000000981:diagnostic imaging; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D008963:Molar / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D019252:Radiography, Dental, Digital / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data; D011862:Radiography, Panoramic / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data