Effect of bit depth and kVp of digital radiography for detection of subtle differences.
OBJECTIVE
The purpose of this study is to investigate the effects of different bit depths and kilovoltage peak (kVp) values used in intraoral digital radiography on observer performance in detecting subtle radiographic density differences.


METHODS
Using an intraoral CCD sensor set at 8- or 12-bit depth, kVp set at 60 or 70, and 14 different exposure times, digital radiographs were acquired of a specially designed aluminum step-wedge phantom with small holes of different depths in each step. Ten observers examined all images.


RESULTS
The observers counted more holes with the 12-bit images compared with the 8-bit images, particularly at 60 kVp. Significantly more holes were also counted with images taken at 70 kVp compared with those taken at 60 kVp.


CONCLUSIONS
Regarding the detection of subtle radiographic density differences, 12-bit images and 70 kVp were superior to 8-bit images and 60 kVp.
Heo
Min-Suk
MS
Department of Oral and Maxillofacial Radiology, BK21 and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
Choi
Da-Hye
DH
Benavides
Erika
E
Huh
Kyung-Hoe
KH
Yi
Won-Jin
WJ
Lee
Sam-Sun
SS
Choi
Soon-Chul
SC
D000704:Analysis of Variance; D006801:Humans; D015588:Observer Variation; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D019252:Radiography, Dental, Digital / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity