X‐ray scatter correction for dedicated cone beam breast CT using a forward‐projection model

Purpose The quality of dedicated cone‐beam breast CT (CBBCT) imaging is fundamentally limited by x‐ray scatter contamination due to the large irradiation volume. In this paper, we propose a scatter correction method for CBBCT using a novel forward‐projection model with high correction efficacy and reliability. Method We first coarsely segment the uncorrected, first‐pass, reconstructed CBBCT images into binary‐object maps and assign the segmented fibroglandular and adipose tissue with the correct attenuation coefficients based on the mean x‐ray energy. The modified CBBCT are treated as the prior images toward scatter correction. Primary signals are first estimated via forward projection on the modified CBBCT. To avoid errors caused by inaccurate segmentation, only sparse samples of estimated primary are selected for scatter estimation. A Fourier‐Transform based algorithm, herein referred to as local filtration hereafter, is developed to efficiently estimate the global scatter distribution on the detector. The scatter‐corrected images are obtained by removing the estimated scatter distribution from measured projection data. Results We evaluate the method performance on six patients with different breast sizes and shapes representing the general population. The results show that the proposed method effectively reduces the image spatial non‐uniformity from 8.27 to 1.91% for coronal views and from 6.50 to 3.00% for sagittal views. The contrast‐to‐deviation ratio is improved by an average factor of 1.41. Comparisons on the image details reveal that the proposed scatter correction successfully preserves fine structures of fibroglandular tissues that are lost in the segmentation process. Conclusion We propose a highly practical and efficient scatter correction algorithm for CBBCT via a forward‐projection model. The method is attractive in clinical CBBCT imaging as it is readily implementable on a clinical system without modifications in current imaging protocols or system hardware.

[1]  J Michael O'Connor,et al.  Characterization of scatter in cone-beam CT breast imaging: comparison of experimental measurements and Monte Carlo simulation. , 2009, Medical physics.

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

[3]  Ruola Ning,et al.  Scatter correction for clinical cone beam CT breast imaging based on breast phantom studies. , 2011, Journal of X-ray science and technology.

[4]  J. Star-Lack,et al.  Improved scatter correction using adaptive scatter kernel superposition , 2010, Physics in medicine and biology.

[5]  Freek J. Beekman,et al.  Efficient Monte Carlo based scatter artifact reduction in cone-beam micro-CT , 2006, IEEE Transactions on Medical Imaging.

[6]  J. Boone,et al.  Dedicated breast CT: initial clinical experience. , 2008, Radiology.

[7]  Klaus Klingenbeck,et al.  A general framework and review of scatter correction methods in x-ray cone-beam computerized tomography. Part 1: Scatter compensation approaches. , 2011, Medical physics.

[8]  Lei Zhu,et al.  Library-based scatter correction for dedicated cone beam breast CT: a feasibility study , 2016, SPIE Medical Imaging.

[9]  X Liu,et al.  A post-reconstruction method to correct cupping artifacts in cone beam breast computed tomography. , 2007, Medical physics.

[10]  Lei Zhu,et al.  Quantitative cone-beam CT imaging in radiation therapy using planning CT as a prior: first patient studies. , 2012, Medical physics.

[11]  Freek J Beekman,et al.  Hybrid scatter correction applied to quantitative holmium-166 SPECT , 2006, Physics in medicine and biology.

[12]  Srinivasan Vedantham,et al.  Dedicated breast CT: fibroglandular volume measurements in a diagnostic population. , 2012, Medical physics.

[13]  J A Seibert,et al.  X-ray scatter removal by deconvolution. , 1988, Medical physics.

[14]  I. Sechopoulos,et al.  Cupping artifact correction and automated classification for high-resolution dedicated breast CT images. , 2012, Medical physics.

[15]  Lei Zhu,et al.  Library based x-ray scatter correction for dedicated cone beam breast CT. , 2016, Medical physics.

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

[17]  D. Jaffray,et al.  Efficient scatter distribution estimation and correction in CBCT using concurrent Monte Carlo fitting. , 2014, Medical physics.

[18]  J. Boone,et al.  Evaluation of x-ray scatter properties in a dedicated cone-beam breast CT scanner. , 2005, Medical physics.

[19]  A. Karellas,et al.  The Potential Role of Dedicated 3D Breast CT as a Diagnostic Tool: Review and Early Clinical Examples , 2014, The breast journal.

[20]  Wei Zhao,et al.  A model-based scatter artifacts correction for cone beam CT. , 2016, Medical physics.

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

[22]  Radhe Mohan,et al.  Scatter kernel estimation with an edge-spread function method for cone-beam computed tomography imaging , 2008, Physics in medicine and biology.

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

[24]  Marc Kachelrieß,et al.  Hybrid scatter correction for CT imaging. , 2012, Physics in medicine and biology.

[25]  A. Karellas,et al.  Dedicated Breast CT: Feasibility for Monitoring Neoadjuvant Chemotherapy Treatment , 2014, Journal of clinical imaging science.

[26]  Biao Chen,et al.  Cone-beam volume CT breast imaging: feasibility study. , 2002, Medical physics.

[27]  John M Boone,et al.  Contrast-enhanced dedicated breast CT: initial clinical experience. , 2010, Radiology.

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

[29]  J. Boone,et al.  Dedicated breast CT: radiation dose and image quality evaluation. , 2001, Radiology.

[30]  Kai Yang,et al.  A breast-specific, negligible-dose scatter correction technique for dedicated cone-beam breast CT: a physics-based approach to improve Hounsfield Unit accuracy , 2014, Physics in medicine and biology.

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

[32]  R L Siddon,et al.  Calculation of the radiological depth. , 1985, Medical physics.

[33]  Srinivasan Vedantham,et al.  Dedicated breast CT: radiation dose for circle-plus-line trajectory. , 2012, Medical physics.