Image reconstruction using a rebinned backprojection-filtration algorithm in half-fan cone-beam CT

Department of Nuclear and Quantum Engineering, KAIST†, Samsung Medical Center††

Yoo, Boyeol†, Pua, Rizza†, Cho, Seungryoung†, Kim, Jinsung††

PURPOSE

제 44회 한국의학물리 춘계학술대회

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To improve the quality of reconstructed image by using a rebinned backprojection-filtration algorithm in half-fan cone-beam CT.

MATERIAL AND METHOD

Chord-based backprojection-filtration (BPF) algorithm is one of the mathematically exact algorithms for image reconstruction in cone-beam CT, and can reconstruct region-of-interest images more robustly from truncated data than filtered-backprojection algorithms. Because of a limited size of detector in CBCT systems, a half-fan scanning mode is usually preferred. Data rebinning is a process of converting the acquired cone-beam data into the parallel-fan data, through which a better image quality is expected.  It is due to the fact that the backprojection does not involve spatially varying weighting factors in the rebinned reconstruction scheme. We implemented the half-fan BPF algorithms in both conventional and rebinned fashions, and compared the reconstructed image qualities.

RESULTS

The reconstructed image by using the conventional BPF algorithm suffered shading artifacts. However, the rebinned BPF algorithm reconstructed accurate images that are free from the shading artifacts.

CONCLUSIONS

The rebinned BPF algorithm outperformed the conventional BPF algorithm in half-fan CBCT image reconstruction in terms of image quality and accuracy.  The developed rebinned BPF algorithm for half-fan CBCT would be very useful for many reconstruction applications including intensity-weighted region-of-interest imaging for low-dose CT.

ACKNOWLEDGEMENT

중심단어: Cone-beam CT, Rebinned backprojection-filtration algorithm, Image reconstruction