Low-Dose and Scatter-Free Cone-Beam CT Imaging Using a Stationary Beam Blocker in a Single Scan: Phantom Studies

Excessive imaging dose from repeated scans and poor image quality mainly due to scatter contamination are the two bottlenecks of cone-beam CT (CBCT) imaging. Compressed sensing (CS) reconstruction algorithms show promises in recovering faithful signals from low-dose projection data but do not serve well the needs of accurate CBCT imaging if effective scatter correction is not in place. Scatter can be accurately measured and removed using measurement-based methods. However, these approaches are considered unpractical in the conventional FDK reconstruction, due to the inevitable primary loss for scatter measurement. We combine measurement-based scatter correction and CS-based iterative reconstruction to generate scatter-free images from low-dose projections. We distribute blocked areas on the detector where primary signals are considered redundant in a full scan. Scatter distribution is estimated by interpolating/extrapolating measured scatter samples inside blocked areas. CS-based iterative reconstruction is finally carried out on the undersampled data to obtain scatter-free and low-dose CBCT images. With only 25% of conventional full-scan dose, our method reduces the average CT number error from 250 HU to 24 HU and increases the contrast by a factor of 2.1 on Catphan 600 phantom. On an anthropomorphic head phantom, the average CT number error is reduced from 224 HU to 10 HU in the central uniform area.

[1]  T. Zhu.  Overview of X-ray Scatter in Cone-beam Computed Tomography and Its Correction Methods , 2010 .

[2]  Xiaochuan Pan,et al.  Image reconstruction in regions-of-interest from truncated projections in a reduced fan-beam scan , 2005, Physics in medicine and biology.

[3]  Xun Jia,et al.  Relationship between x-ray illumination field size and flat field intensity and its impacts on x-ray imaging. , 2012, Medical physics.

[4]  Lei Zhu,et al.  Shading correction for on-board cone-beam CT in radiation therapy using planning MDCT images. , 2010, Medical physics.

[5]  Timothy D. Solberg,et al.  Image-guided radiotherapy using a mobile kilovoltage x-ray device. , 2006 .

[6]  J. Boone,et al.  An analytical model of the scattered radiation distribution in diagnostic radiology. , 1988, Medical physics.

[7]  W. Kalender,et al.  Combining deterministic and Monte Carlo calculations for fast estimation of scatter intensities in CT , 2006, Physics in medicine and biology.

[8]  Yaakov Tsaig,et al.  Extensions of compressed sensing , 2006, Signal Process..

[9]  E. Sidky,et al.  Image reconstruction in circular cone-beam computed tomography by constrained, total-variation minimization , 2008, Physics in medicine and biology.

[10]  A. Macovski,et al.  Dual-energy x-ray projection imaging: two sampling schemes for the correction of scattered radiation. , 1988, Medical physics.

[11]  D. Jaffray,et al.  Cone-beam computed tomography with a flat-panel imager: magnitude and effects of x-ray scatter. , 2001, Medical physics.

[12]  W. Kalender,et al.  Technical note: comparing coherent and incoherent scatter effects for cone-beam CT , 2008, Physics in medicine and biology.

[13]  D. Hristov,et al.  Cone beam X-ray scatter removal via image frequency modulation and filtering , 2005, 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference.

[14]  D. Jaffray,et al.  Optimization of x-ray imaging geometry (with specific application to flat-panel cone-beam computed tomography). , 2000, Medical physics.

[15]  Nelson Lam,et al.  Radiation dose from cone beam computed tomography for image-guided radiation therapy. , 2008, International journal of radiation oncology, biology, physics.

[16]  N. R. Bennett,et al.  Scatter correction method for x-ray CT using primary modulation: phantom studies. , 2010, Medical physics.

[17]  Timothy D. Solberg,et al.  Scatter correction for cone-beam computed tomography using moving blocker strips: a preliminary study. , 2010 .

[18]  D. Jaffray,et al.  The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors. , 2004, Medical physics.

[19]  Freek J. Beekman,et al.  Accelerated simulation of cone beam X-ray scatter projections , 2004, IEEE Transactions on Medical Imaging.

[20]  Steve B. Jiang,et al.  GPU-based fast cone beam CT reconstruction from undersampled and noisy projection data via total variation. , 2010, Medical physics.

[21]  Taewon Lee,et al.  Feasibility study on many-view under-sampling technique for low-dose computed tomography , 2012 .

[22]  Lei Zhu,et al.  An Efficient Estimation Method for Reducing the Axial Intensity Drop in Circular Cone-Beam CT , 2008, Int. J. Biomed. Imaging.

[23]  Hao Yan,et al.  A GPU tool for efficient, accurate, and realistic simulation of cone beam CT projections. , 2012, Medical physics.

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

[25]  Steve B. Jiang,et al.  The management of imaging dose during image-guided radiotherapy: report of the AAPM Task Group 75. , 2007, Medical physics.

[26]  Christopher J Moore,et al.  A feasibility study for image guided radiotherapy using low dose, high speed, cone beam X-ray volumetric imaging. , 2005, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[27]  Ruola Ning,et al.  X-ray scatter correction algorithm for cone beam CT imaging. , 2004, Medical physics.

[28]  M. Endo,et al.  Effect of scattered radiation on image noise in cone beam CT. , 2001, Medical physics.

[29]  Lei Zhu,et al.  Modulator design for x-ray scatter correction using primary modulation: material selection. , 2010, Medical physics.

[30]  Rebecca Fahrig,et al.  A short-scan reconstruction for cone-beam CT using shift-invariant FBP and equal weighting. , 2007, Medical physics.

[31]  Lei Zhu,et al.  Accelerated barrier optimization compressed sensing (ABOCS) reconstruction for cone-beam CT: Phantom studies. , 2012, Medical physics.

[32]  Lei Zhu,et al.  Scatter correction for full-fan volumetric CT using a stationary beam blocker in a single full scan. , 2011, Medical physics.

[33]  D. Brenner,et al.  Computed tomography--an increasing source of radiation exposure. , 2007, The New England journal of medicine.

[34]  E. Sidky,et al.  Accurate image reconstruction from few-views and limited-angle data in divergent-beam CT , 2009, 0904.4495.

[35]  J. Pouliot,et al.  Focused beam-stop array for the measurement of scatter in megavoltage portal and cone beam CT imaging. , 2008, Medical physics.

[36]  Xun Jia,et al.  Low-dose and scatter-free cone-beam CT imaging: a preliminary study , 2012, Medical Imaging.

[37]  Lei Zhu,et al.  X-ray scatter correction for cone-beam CT using moving blocker array , 2005, SPIE Medical Imaging.

[38]  Charles W. Coffey,et al.  Radiation dose from kilovoltage cone beam computed tomography in an image-guided radiotherapy procedure. , 2009, International journal of radiation oncology, biology, physics.

[39]  Gyuseong Cho,et al.  Backprojection-filtration image reconstruction from partial cone-beam data for scatter correction , 2011, Medical Imaging.

[40]  Lei Zhu,et al.  Noise suppression in scatter correction for cone-beam CT. , 2009, Medical physics.

[41]  Lei Zhu,et al.  Scatter Correction Method for X-Ray CT Using Primary Modulation: Theory and Preliminary Results , 2006, IEEE Transactions on Medical Imaging.

[42]  Steve B. Jiang,et al.  Low-dose CT reconstruction via edge-preserving total variation regularization. , 2010, Physics in medicine and biology.

[43]  Lei Zhu,et al.  Scatter correction for cone-beam CT in radiation therapy. , 2009 .