Above is a demonstration of a randomly rotated (within, ±2°) and translated (within, ±5 mm) CT data set (see bottom right inset) around the plan isocenter location (cross‐hair) for a representative patient (one fraction). The PTVs are shown in orange and pink and the GTVs are in red in both lungs. Normal structures are shown: lungs (light blue and green), skin (purple), cord (yellow), and ribs (blue). This patient was treated for 50 Gy in 5 fractions to both tumors, thus the random transformation process was repeated for a total of five treatments (see top left inset).