Reduction in x-ray scatter and radiation dose for volume-of-interest (VOI) cone-beam breast CT--a phantom study.

With volume-of-interest (VOI) cone-beam computed tomography (CBCT) imaging, one set of projection images are acquired with the VOI collimator at a regular or high exposure level and the second set of projection images are acquired without the collimator at a reduced exposure level. The high exposure VOI scan data inside the VOI and the low exposure full-field scan data outside the VOI are then combined together to generate composite projection images for image reconstruction. To investigate and quantify scatter reduction, dose saving and image quality improvement in VOI CBCT imaging, a flat panel detector-based bench-top experimental CBCT system was built to measure the dose, the scatter-to-primary ratio (SPR), the image contrast, noise level, the contrast-to-noise ratio (CNR) and the figure of merit (FOM) in the CBCT reconstructed images for two polycarbonate cylinders simulating the small and the large phantoms. The results showed that, compared to the full field CBCT technique, radiation doses for the VOI CBCT technique were reduced by a factor of 1.20 and 1.36 for the small and the large phantoms at the phantom center, respectively, and from 2.7 to 3.0 on the edge of the phantom, respectively. Inside the VOI, the SPRs were substantially reduced by a factor of 6.6 and 10.3 for the small and the large phantoms, the contrast signals were improved by a factor of 1.35 and 1.8, and the noise levels were increased by a factor of 1.27 and 1.6, respectively. As a result, the CNRs were improved by a factor of 1.06 and 1.13 for the small and the large phantoms and the FOM improved by a factor of 1.4 and 1.7, respectively.

[1]  Thomas R. Nelson,et al.  Performance assessment of a pendant-geometry CT scanner for breast cancer detection , 2005, SPIE Medical Imaging.

[2]  Yong Yu,et al.  Evaluation of flat panel detector cone beam CT breast imaging with different sizes of breast phantoms , 2005, SPIE Medical Imaging.

[3]  Lingyun Chen,et al.  Visibility of microcalcification in cone beam breast CT: effects of X-ray tube voltage and radiation dose. , 2007, Medical physics.

[4]  T Bortfeld,et al.  Correction of scatter in megavoltage cone-beam CT , 2001, Physics in medicine and biology.

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

[6]  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.

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

[8]  C. D'Orsi,et al.  Clinical comparison of full-field digital mammography and screen-film mammography for detection of breast cancer. , 2002, AJR. American journal of roentgenology.

[9]  Aruna A. Vedula,et al.  A computer simulation study comparing lesion detection accuracy with digital mammography, breast tomosynthesis, and cone-beam CT breast imaging. , 2006, Medical physics.

[10]  Selin Carkaci,et al.  Dedicated cone-beam breast CT: feasibility study with surgical mastectomy specimens. , 2007, AJR. American journal of roentgenology.

[11]  Srinivasan Vedantham,et al.  Investigation of optimal kVp settings for CT mammography using a flat-panel imager , 2002, SPIE Medical Imaging.

[12]  S Rudin,et al.  Region of interest (ROI) computed tomography , 2004, SPIE Medical Imaging.

[13]  Aruna A. Vedula,et al.  Microcalcification detection using cone-beam CT mammography with a flat-panel imager. , 2004, Physics in medicine and biology.

[14]  P. Huynh,et al.  The false-negative mammogram. , 1998, Radiographics : a review publication of the Radiological Society of North America, Inc.

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

[16]  Lingyun Chen,et al.  Feasibility of volume-of-interest (VOI) scanning technique in cone beam breast CT--a preliminary study. , 2008, Medical physics.

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

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

[19]  S Rudin,et al.  Region of interest (ROI) computed tomography (CT): comparison with full field of view (FFOV) and truncated CT for a human head phantom , 2005, SPIE Medical Imaging.

[20]  Ruola Ning,et al.  Flat-panel detector-based cone-beam volume CT breast imaging: preliminary phantom study , 2001, SPIE Medical Imaging.

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

[22]  Samta Thacker,et al.  A comparison of lesion detection accuracy using digital mammography and flat-panel CT breast imaging (Honorable Mention Poster Award) , 2005, SPIE Medical Imaging.

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

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

[25]  T R Nelson,et al.  A comprehensive analysis of DgN(CT) coefficients for pendant-geometry cone-beam breast computed tomography. , 2004, Medical physics.

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

[27]  Huiguang He,et al.  Preliminary system characterization of flat-panel-detector-based cone-beam CT for breast imaging , 2004, SPIE Medical Imaging.

[28]  Tianpeng Wang,et al.  An accurate scatter measurement and correction technique for cone beam breast CT imaging using scanning sampled measurement (SSM)technique , 2006, SPIE Medical Imaging.