Obtaining the CT mask

[Wapity]

Hello,

Thank you for this outstanding work,
I would like to obtain the CT mask for bedstripping,
It seems this mask is not only external contour but helps for better realism of the attenuations?
Because the DRRs I obtain vary a lot between patients, some we can see internal organs, some we see only the bones, do you think it is normal?
Thank you very much for an answer