Fully iterative scatter corrected digital breast tomosynthesis using GPU‐based fast Monte Carlo simulation and composition ratio update. Issue 9 (19th August 2015)

• Record Type: Journal Article
• Authors: Kim, Kyungsang; Lee, Taewon; Seong, Younghun; Lee, Jongha; Jang, Kwang Eun; Choi, Jaegu; Choi, Young Wook; Kim, Hak Hee; Shin, Hee Jung; Cha, Joo Hee; Cho, Seungryong; Ye, Jong Chul
• Is Part Of: Medical physics. Volume 42:Issue 9(2015)
• Page Start: 5342
• Page End: 5355
• Publication Date: 2015-08-19
• Subjects: biological tissues -- Compton effect -- computerised tomography -- graphics processing units -- image reconstruction -- iterative methods -- medical image processing -- Monte Carlo methods -- photoelectricity -- radiology -- Rayleigh scattering; Computed tomography -- X‐ray imaging -- Numerical approximation and analysis -- Monte Carlo simulations -- Reconstruction; Computerised tomographs -- Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Processor architectures; Processor configuration, e.g. pipelining; digital breast tomosynthesis -- scatter correction -- Monte Carlo simulation -- composition ratio update -- GPU; X‐ray scattering -- Optical microcavities -- Photons -- Medical image reconstruction -- Photon scattering -- Image sensors -- Image reconstruction -- Compton scattering -- Medical image quality; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4928139
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: In digital breast tomosynthesis (DBT), scatter correction is highly desirable, as it improves image quality at low doses. Because the DBT detector panel is typically stationary during the source rotation, antiscatter grids are not generally compatible with DBT; thus, a software‐based scatter correction is required. This work proposes a fully iterative scatter correction method that uses a novel fast Monte Carlo simulation (MCS) with a tissue‐composition ratio estimation technique for DBT imaging. Methods: To apply MCS to scatter estimation, the material composition in each voxel should be known. To overcome the lack of prior accurate knowledge of tissue composition for DBT, a tissue‐composition ratio is estimated based on the observation that the breast tissues are principally composed of adipose and glandular tissues. Using this approximation, the composition ratio can be estimated from the reconstructed attenuation coefficients, and the scatter distribution can then be estimated by MCS using the composition ratio. The scatter estimation and image reconstruction procedures can be performed iteratively until an acceptable accuracy is achieved. For practical use, (i) the authors have implemented a fast MCS using a graphics processing unit (GPU), (ii) the MCS is simplified to transport only x‐rays in the energy range of 10–50 keV, modeling Rayleigh and Compton scattering and the photoelectric effect using the tissue‐composition ratio of adipose and glandular tissues, and (iii) downsampling is used because the scatter distribution varies rather smoothly. Results: The authors have demonstrated that the proposed method can accurately estimate the scatter distribution, and that the contrast‐to‐noise ratio of the final reconstructed image is significantly improved. The authors validated the performance of the MCS by changing the tissue thickness, composition ratio, and x‐ray energy. The authors confirmed that the tissue‐composition ratio estimation was quite accurate under a variety of conditions. Our GPU‐based fast MCS implementation took approximately 3 s to generate each angular projection for a 6 cm thick breast, which is believed to make this process acceptable for clinical applications. In addition, the clinical preferences of three radiologists were evaluated; the preference for the proposed method compared to the preference for the convolution‐based method was statistically meaningful ( p < 0.05, McNemar test). Conclusions: The proposed fully iterative scatter correction method and the GPU‐based fast MCS using tissue‐composition ratio estimation successfully improved the image quality within a reasonable computational time, which may potentially increase the clinical utility of DBT.