Program Information
Motion Artifacts Reduction in Gas Pockets for Conebeam CT in Radiation Therapy
Y Xue , C Yang , Y Jiang*, T Niu , Zhejiang University, Hangzhou, Zhejiang
Presentations
SU-F-201-7 (Sunday, July 30, 2017) 2:05 PM - 3:00 PM Room: 201
Purpose: In conebeam CT (CBCT) image, severe streaking and shading artifacts are produced in the abdominal region around the high-contrast objects including the gas pockets and bony structures due to respiratory and intestines peristalsis, and an optimal motion-artifacts reduction solution remains unclear. Here we proposed a new motion artifacts reduction method for CBCT based on signal processing technique.
Methods: Due to the irregularity of the motion artifacts and the unmatched projections acquisition, motion caused artifacts are separated into shading and streaking artifacts. Since motion induced shading artifacts exist in the same location as the high-contrast gas pockets, shading artifacts are corrected for using localized Radon transform on the shading contaminated area and replacing contaminated projection data with linear interpolation in the simulated projection. Frequency splitting analysis is then applied to extract the noise, edges and streaking artifacts with aliasing frequency in the image domain. Streaking artifacts are finally selected within the simulated projection at the location of gas pockets and bony structure. The selected streaking artifacts are then reconstructed and subtracted directly from the shading corrected image in the image domain.
Results: The proposed method is evaluated on one abdominal patient. Severe motion artifacts are significantly suppressed. Overall CT number error is reduced from over 90HU to be less than 20HU using our method.
Conclusion: Effective motion artifacts reduction is achieved on CBCT using our signal processing method. The increased accuracy of CBCT imaging substantially facilitates CBCT-based clinical applications. It is thus attractive for radiation therapy.
Funding Support, Disclosures, and Conflict of Interest: Zhejiang Provincial Natural Science Foundation of China (Grant No. LR16F010001) National High-tech R&D Program for Young Scientists by the Ministry of Science and Technology of China (863 Program, 2015AA020917)
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