Use of a Total Variation Minimization Iterative Reconstruction Algorithm to Evaluate Reduced Projections during Digital Breast Tomosynthesis

Figure 2

The adaptive steepest descent projection onto the convex sets algorithm in the form of a pseudocode. : the ART operator depends on the relaxation parameter. : the ART-relaxation parameter is reduced by a constant fraction. : total variation (TV) hyperparameter. , : these variables control the evolution of . : iteration number for the TV-steepest descent. Image-space variables are denoted by a vector sign (e.g., ). Data-space variables are denoted by a tilde (e.g., ). The vector is the row of the system matrix that produces the th data element. is the optimization problem specified by the projection. is the data-inconsistency-tolerance parameter (reference: Sidky EY, Pan X. Image reconstruction in circular cone-beam computed tomography by constrained, total variation minimization. Phys Med Biol, 2008; 53: p.4788).