Cone-beam CT using a C-arm system as front end and a spherical spiral as source trajectory

C-arm systems may be used as front ends for cone-beam CT. The resulting image quality is affected by several factors, including the source trajectory, the reconstruction algorithm, and the accuracy of the data. The standard source trajectory is a circular arc spanning a little more than 180 degrees. However, since a planar source trajectory satisfies Tuy's completeness condition only within a subset of the source plane, the resulting images are bound to exhibit "cone-beam artifacts" off the source plane. The cure consists in using a source trajectory that satisfies Tuy's completeness condition everywhere within the volume of interest. Such a source trajectory must be non-planar. To keep the scan time short, the source trajectory should also consist of a single, smooth segment. A favorable source trajectory of this kind is a curve known as spherical spiral. We implemented a spherical spiral on a laboratory C-arm system, along with a standard circular arc. An anthropomorphic head phantom was scanned using both source trajectories and otherwise identical scan parameters. Images were reconstructed using a short scan version of the FDK algorithm (circular arc) and the cone-beam Fourierfiltered backprojection (CBFFBP) algorithm presented earlier. Images obtained with the circular arc showed cone-beam artifacts. Images obtained with the spherical spiral did not. The results also demonstrate the good performance of the CBFFBP algorithm.

[1]  D L Parker,et al.  Optimal short scan convolution reconstruction for fanbeam CT. , 1982, Medical physics.

[2]  A. Katsevich.  A GENERAL SCHEME FOR CONSTRUCTING INVERSION ALGORITHMS FOR CONE BEAM CT , 2003 .

[3]  Rolf Clackdoyle,et al.  Cone-beam reconstruction using the backprojection of locally filtered projections , 2005, IEEE Transactions on Medical Imaging.

[4]  Tsuneo Saito,et al.  Derivation and implementation of a cone-beam reconstruction algorithm for nonplanar orbits , 1994, IEEE Trans. Medical Imaging.

[5]  L. Feldkamp,et al.  Practical cone-beam algorithm , 1984 .

[6]  T. Zhuang,et al.  New families of exact fan-beam and cone-beam image reconstruction formulae via filtering the backprojection image of differentiated projection data along singly measured lines , 2006 .

[7]  J. Hornegger,et al.  Cone-beam Tomography from Short-Scan Circle-plus-Arc Data Measured on a C-arm System , 2006, 2006 IEEE Nuclear Science Symposium Conference Record.

[8]  F. Noo,et al.  Cone-beam reconstruction using 1D filtering along the projection of M-lines , 2005 .

[9]  D. Bertsekas.  6.253 Convex Analysis and Optimization, Spring 2010 , 2004 .

[10]  Hermann Schomberg,et al.  Image reconstruction from truncated cone-beam projections , 2004, 2004 2nd IEEE International Symposium on Biomedical Imaging: Nano to Macro (IEEE Cat No. 04EX821).

[11]  Rolf Clackdoyle,et al.  A cone-beam reconstruction algorithm using shift-variant filtering and cone-beam backprojection , 1994, IEEE Trans. Medical Imaging.

[12]  Mark W. Spong,et al.  Robot dynamics and control , 1989 .

[13]  H. Tuy.  AN INVERSION FORMULA FOR CONE-BEAM RECONSTRUCTION* , 1983 .

[14]  ALEXANDER KATSEVICH,et al.  Filtered Backprojection Inversion of the Cone Beam Transform for a General Class of Curves , 2007, SIAM J. Appl. Math..

[15]  Alfred Gray,et al.  Modern differential geometry of curves and surfaces with Mathematica (2. ed.) , 1998 .

[16]  Hengyong Yu,et al.  A general exact reconstruction for cone-beam CT via backprojection-filtration , 2005, IEEE Transactions on Medical Imaging.

[17]  Xiaochuan Pan,et al.  Theory and algorithms for image reconstruction on chords and within regions of interest. , 2005, Journal of the Optical Society of America. A, Optics, image science, and vision.

[18]  Hermann Schomberg,et al.  Complete Source Trajectories for CArm Systems and a Method for Coping with Truncated Cone-Beam Projections , 2001 .

[19]  R M Lewitt,et al.  Processing of incomplete measurement data in computed tomography. , 1979, Medical physics.

[20]  Ge Wang,et al.  Filtered backprojection formula for exact image reconstruction from cone-beam data along a general scanning curve. , 2004, Medical physics.

[21]  Hengyong Yu,et al.  A unified framework for exact cone-beam reconstruction formulas. , 2005, Medical physics.

[22]  D. Babic,et al.  Brain imaging with a flat detector C-arm , 2008, Neuroradiology.

[23]  S. Leng,et al.  Fan-beam and cone-beam image reconstruction via filtering the backprojection image of differentiated projection data , 2004, Physics in medicine and biology.