Abstract
PURPOSE: This study was performed to establish a procedure for simulated low-dose cone-beam computed tomography (CBCT) scans and to investigate whether the resulting images are comparable in diagnostic accuracy to those obtained using a clinical low-dose protocol. MATERIALS AND METHODS: ImageJ was used to manipulate the sinogram data from CBCT scans acquired at 5 mA to mimic a technical setting of 2 mA by adding noise to the Radon-transformed projection data before image reconstruction. Four observers compared the simulated 2 mA CBCT scans with original clinical 2 mA CBCT scans acquired previously. The CBCT images were analysed using a protocol with a ranking scale, and the observers were required to select only 1 category for each variable. The Wilcoxon signed-rank test was used to assess differences between the 2 CBCT scan types, with a significance level of P<0.05. Intra-observer agreement was evaluated using the Cohen kappa. RESULTS: Pairwise observer comparisons of the simulated and clinical low-dose CBCT scans showed no significant differences in image quality. Intra-observer agreement was acceptable, and in 5 comparisons, the results indicated a high degree of agreement. CONCLUSION: Simulated low-dose CBCT scans can be generated using ImageJ. No significant differences in image quality were observed between simulated and clinical low-dose CBCT scans when evaluating mandibular third molars. These findings suggest that manipulation of sinogram data is a promising radiation-free approach for simulating low-dose images in optimisation efforts.