Tissue structure
Variable
β
SE
p
GTV
GTV volume (cc)
-0.008
0.004
0.04
GTV
PTV volume (cc)
-0.004
0.002
0.03
PTV
GTV volume (cc)
-0.012
0.004
0.01
PTV
PTV volume (cc)
-0.005
0.002
0.01
PTV
Total MU
-0.006
0.003
0.04
PTV
Number of fields
-0.407
0.308
0.20
Esophagus
Total MU
-0.003
0.001
<0.01
Esophagus
Number of fields
-0.181
0.109
0.11

Abbreviations: SE = Standard Error; β = change in mean dose difference per unit change of the independent variable.

Table 5: Univariate analysis of factors associated with the difference in mean dose between the pencil beam (PB) and Monte Carlo (MC) algorithms for tissue structures GTV, PTV, and esophagus.