A Novel Implementation of the Backprojected Filtration Algorithm for Helical Cone­beam CT

Yunsong Zhao1, Yining Zhu1, and Peng Zhang1

1The CT Laboratory, School of Mathematics, Capital Normal University, Beijing 100048, China.

E­mail: pzhangct@sina.com.

ABSTRACT

To solve the long­object problem, helical cone­beam scanning configuration was proposed, and several exact or approximate reconstruction algorithms were invented. Compared with approximate algorithms (like FDK algorithm), exact algorithms are free of cone­beam artifacts. Fast implementation of exact reconstruction algorithms are of high importance in clinical and industrial application. In the present paper, we propose a new implementation of the backprojected filtration algorithm for helical cone­beam CT. The advantages of our implementation are: (i) it can directly reconstruct horizontal slices, avoiding 3­D interpolation; (ii) it needs not to calculate the backprojection interval for any point; (iii) it is of high degree of parallelism and is suitable for acceleration on GPU (Graphic Processing Unit) or other parallel systems.

Keywords Cone­beam tomography, helical CT, horizontal slice reconstruction, fast implementation.