Chen (corresponding author), “Statistical iterative reconstruction using fast optimization transfer algorithm with successively increasing factor in Digital Breast Tomosynthesis,”
Chen (corresponding author), “Parameter Optimization of relaxed Ordered Subsets Pre-computed Back Projection (BP) based Penalized-Likelihood (OS-PPL) Reconstruction in Limited-angle X-ray Tomography,” , Vol.
Dobbins III, “Methodology of f) Analysis for Optimization and Comparison of Digital Breast Tomosynthesis Acquisition Techniques and Reconstruction Algorithms,” , Vol.
Dobbins III, “Gaussian Frequency Blending Algorithm with Matrix Inversion Tomosynthesis (MITS) and Filtered Back Projection (FBP) for Better Digital Breast Tomosynthesis Reconstruction,” , Vol.
Dobbins III, “A Comparison between Traditional Shift-and add (SAA) and Point-by-point Back Projection (BP) – Relevance to Morphology of for Motion in Digit Breast Tomosynthesis (DBT)”,, Vol.
Chen (corresponding author) “An application of pre-computing based penalized-likelihood image reconstruction on stationary digital breast tomosynthesis”,
Chen (corresponding author), “Pre-computed back-projection based penalized-likelihood (PPL) reconstruction with an edge-preserved for stationary digital breast tomosynthesis,”
Digital breast tomosynthesis (DBT) is an emerging imaging modality which produces three-dimensional radiographic images of breast. DBT reconstructs tomographic images from a limited view angle, thus data acquired from DBT is not sufficient enough to reconstruct an exact image. It was proven that a sparse image from a highly undersampled data can be reconstructed via compressed sensing (CS) techniques. This can be done by minimizing the l1 norm of the gradient of the image which can also be defined as total variation (TV) minimization. In tomosynthesis imaging problem, this idea was utilized by minimizing total variation of image reconstructed by algebraic reconstruction technique (ART). Previous studies have largely addressed 2-dimensional (2D) TV minimization and only few of them have mentioned 3-dimensional (3D) TV minimization. However, quantitative analysis of 2D and 3D TV minimization with ART in DBT imaging has not been studied.
A 3D phantom which roughly simulates a breast tomosynthesis image was designed to evaluate the performance of the methods both quantitatively and qualitatively in the sense of visual assessment, structural similarity (SSIM), root means square error (RMSE) of a specific layer of interest (LOI) and total error values. Both methods show superior results in reducing out-of-focus slice blur compared to ART.
In summary, detectability in tomosynthesis reconstructions for thoracic imaging increases as fixed dose is distributed over a larger acquisition orbital extent (up to 120).AB - Tomosynthesis is an imaging technique that has gained renewed interest with recent advancements of flat-panel digital detectors.
A patient's previous day's CBCT images are used as the prior information, and the new patient volume is considered as a deformation of the prior CBCT volume. The deformation field is solved by minimizing bending energy and maintaining data fidelity with a nonlinear conjugate gradient method. The new on-board DTS image is then obtained by deforming the prior CBCT image volume based on the deformation field solved. The algorithm was tested using prostate and head-and-neck patient data. In prostate patient study, projections simulated from the new CBCT image were used in reconstruction. The accuracy of the reconstruction was evaluated by comparing the volume change of the rectum in DTS and new CBCT images. The pixel signal-to-noise ratio (PSNR) was also calculated to evaluate the pixel value difference between DTS and new CBCT images. In head-and-neck patient study, real on-board projections were used in reconstruction. Blank scans with the full-fan bowtie filter attached were acquired and used to correct the raw projection data before reconstruction. The accuracy of the reconstruction was evaluated by comparing the location of bony structures and the positions of 10 localization points around soft tissue in DTS and new CBCT images.
A novel reconstruction method was developed to reconstruct DTS images using prior information and a deformation model. Volumetric information was optimally estimated using 60 to 90 degrees scan angle. Preliminary validation of the algorithm showed that it is both technically and clinically feasible for image-guidance in radiation therapy.
Dobbins, III, “Impulse Response and Modulation Transfer Function Analysis for Shift-and-Add and Back Projection Image Reconstruction Algorithms in Digital Breast Tomosynthesis (DBT),”