Figure 4. A plot of the value of the standard deviation (1σ) of ${\text{TD}}_1^{\left\{\mu \right\}}$ at each point in the array after 1000 trials of randomly selected motion phases. The values of the standard deviation range from 1.2% to 5.4%. Within the high‐dose region (90% isodose curve), the variation is 2.0% to 3.8%.