How to reslice polydata insert into imagedata?

Hey guys, I am now building a medical project and need some tips.
This project is for surgeon. A doctor need to implant bone nail and interactive with nails.

I have bone image data from CT, and STL file of nails.
I can read both of object, but I don’t know how do implement this project better.
So I come to ask.

Here is the function I need to do

  1. insert nail into bone and the nail can be moved
    I add nail to the position I want and active with vtklinewidget2 for calculate the rotate angle this origin position
  2. I need to reslice whole 3D in window result to 2D slice image, Like below. Here comes the problem.
    I can do reslice with reslicewidget , but when nail is implant. I am not sure how to show slice of nail and set it at right postion.
    Should I concat both of object to imagedata or polydata?
    Is it possible to make slice without extension, only using origin VTK package?

Looking at this code might help:

Is it reslice base on NRMLmarkupNosw?