Structure name
avg ± σ (min, max) %
p (PB vs. MC)
GTV
3.6 ± 2.3 (0.0, 8.4)
<0.01
PTV
4.3 ± 2.8 (0.0, 10.5)
<0.01
Esophagus
0.6 ± 1.0 (-2.6, 2.1)
0.01
Spinal cord
0.2 ± 0.6 (-1.2, 1.1)
0.04
Heart
0.2 ± 0.5 (-1.6, 0.8)
0.12
Table 2: Mean dose difference comparison between the pencil beam (PB) and Monte Carlo (MC) algorithms (i.e., PB – MC) for the GTV, PTV, and OARs for all 25 patients. Note that the lung mean dose is the same as the lung EUD (a = 1). The results for the lungs are reported in Table 4.