Low-dose CBCT reconstruction via joint non-local total variation denoising and cubic B-spline interpolation
- Journal
- Scientific reports
- Vol
- 11
- Page
- 3681
- Year
- Miscellaneous
- File
- Ho Lee_2021_Scientific reports.pdf (3.5M) 6회 다운로드 DATE : 2021-03-14 08:52:44
non-local total variation (NLTV) denoising and a cubic B-spline interpolation-based backprojector
to enhance the image quality of low-dose cone-beam computed tomography (CBCT). The NLTV
objective function is minimized on all log-transformed projections using steepest gradient descent
optimization with an adaptive control of the step size to augment the diference between a real
structure and noise. The proposed algorithm was evaluated using a phantom data set acquired from a
low-dose protocol with lower milliampere-seconds (mAs).The combination of NLTV minimization and
cubic B-spline interpolation rendered the enhanced reconstruction images with signifcantly reduced
noise compared to conventional FDK and local total variation with anisotropic penalty. The artifacts
were remarkably suppressed in the reconstructed images. Quantitative analysis of reconstruction
images using low-dose projections acquired from low mAs showed a contrast-to-noise ratio with
spatial resolution comparable to images reconstructed using projections acquired from high mAs. The
proposed approach produced the lowest RMSE and the highest correlation. These results indicate that
the proposed algorithm enables application of the conventional FDK algorithm for low mAs image
reconstruction in low-dose CBCT imaging, thereby eliminating the need for more computationally
demanding algorithms. The substantial reductions in radiation exposure associated with the low mAs
projection acquisition may facilitate wider practical applications of daily online CBCT imaging.