Table 3.

The list of covariates used to derive eq. 1, 2, 3, 4, 5, 6, 7 and 8. Active pixels refer to the white pixels in binary images

Covariates	Definition
PA	The number of active pixels in A
PB	The number of active pixels in B
P (B∩A)	The number of active pixels that are true for both A and B
n	The number of effected slices
(x,y)	The contour vertices: - - Air pocket contour vertices (xi,yi) - Solid wall contour vertices (xk,yk)
Span	The longest distance between two vertices of the tumor mask
ID	Inner diameter of a lucent area. If more than one area is present, the average is calculated.