Images reconstructed by use of the unweighted dual averaging method with a fixed step size of 0.1 after (a) 20, (b) 50, (c) 100, and (d) 250 iterations. Images reconstructed by use of the weighted dual averaging method after (e) 20, (f) 50, (g) 100, and (h) 250 iterations. All results are shown for a regularization parameter value of 1 × 10−4 and in a grayscale window of [1.47,1.58] mm/μs. The RMSEs for each reconstructed image are displayed in the bottom left of each subfigure.