FIGURE 3.

Case 4: source centered in applicator. Water cube of side 20.1 cm centered in a 51.1 cm side air cube. The generic MBDCA-WG Ir-192 source is centered in the TG-186 shielded applicator. Top-left and middle-left panels: TOPAS scaled relative dose maps in planes z = 0 and y = 0, white regions represent the applicator position. Top-right and middle-right panels: local dose difference ratio ${\text{ΔD}}_{\mathrm{LOCAL}}$ (%) in planes z = 0 and y = 0. Bottom-left and bottom-right panels: histograms of ${\text{ΔD}}_{\mathrm{LOCAL}}$ (%) and ${\text{ΔD}}_{\mathrm{GLOBAL}}$ (%) ratios, respectively.