Representative plots showing the scale ranges (x-axes) corresponding to the linear regions that were used to compute the slope of the graphs from which FD is computed using the (a) variation, (b) power spectrum, and (c) variogram methods. The scale ranges are in terms of the logarithm of the number of pixels for (a) and (c) and the logarithm of the pixel frequency for (b), where a pixel side length = 0.786 mm.
Three representative contour plots of the same IMRT actual fluence field that was planned in Eclipse IMRT using x-y fluence smoothing of (a) 50-40, (b) 30-20, and (c) 20-10 to illustrate the change in modulation with the fluence smoothing parameters. The corresponding variogram fractal dimensions for the plots are: (a) 2.16, (b) 2.22, and (c) 2.27.
Each point on the graphs represents the FD and its associated uncertainty as estimated from the standard deviation of 80 fractional Brownian surfaces of known fractal dimension. Results are shown for: (a) the variation method, (b) the power spectrum method, and (c) the variogram method.
Variogram FD analysis of 7 IMRT fields of the same head and neck case planned using three x-y fluence smoothing parameters. The LAO105 field corresponds to the contour images shown in Fig. 2.
Boxplot displays of the distributions of the variogram FD, number of MUs, average leaf gap, and 2D MI of the moderate and high modulation IMRT fields.
ROC curves representing the classification performance of the variogram FD, number of MUs, average leaf gap, and 2D MI as indicators of moderate versus high modulation IMRT fields.
Boxplot displays of the distributions of the gamma analysis of the planar dose measurements made with the MapCHECK™ 2D diode detector array device. The gamma analyses are shown for different settings of PDD, DTA, Van Dyke gamma criteria, and dose difference threshold.
AUC from the ROC analysis.
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