Aim: To assess the accuracy of ultra-low dose and standard dose CBCT protocols in volumetric measurements of simulated bone defects in comparison with the real physical measurements.
Methodology: A number of 58 defects mimicking periapical lesions were prepared on the ribs of sheep. Actual physical volumetric measurements of the defects were obtained by water displacement method; samples were scanned by ultra-low dose and standard dose CBCT protocols( 90 KVP,8 MA &13 SEC and 90 KVP,5.6 MA& 9 SEC) respectively . Volumetric measurements were done in each scan by two calibrated oral radiologists, with different experience, who were blinded to the parameters of the scans and to the physical measurements. The values of the CBCT volumetric measurements were compared to the physical measurements and statistically analyzed.
Results: The results of this study showed that ultra-low dose had smaller Dahlberge error, smaller Relative Dahlberge error,tighter limits of agreement and higher concordance correlation coefficient than standard dose which means better accuracy of the segmentation procedure using this protocol. A strong positive correlation was found between the two protocols and the physical measurement.
Conclusion: Ultra-low dose CBCT is a suitable protocol in volumetric measurements. As both ultra-low dose protocol and standard dose protocol had a strong correlation with physical measurement, CBCT is a reliable tool in volumetric measurements.