Got variable beam energy working and it's pretty neat to see how it affects the image:
The actual anatomy is fairly approximate right now (bone has no marrow, heart is just a solid mass of muscle without internal details), but the materials and their interaction with the X-rays are real values: physics.nist.gov/PhysRefData/Xr…
but it's really neat to see the math actually work out like the textbooks said
They just don't really reflect off of much, so we make images by casting shadows with them