As shown in figure : I want to measure the CT value of the boundary (the contact interface between the bone and the cylinder) of a certain section of the cylinder in the vertebral pedicle. What should I do?
I once tried to measure by measuring the sum of voxels of each point on the section circle, but this does not seem to reflect the relationship between the circumference and the CT value (I mean, if the SetResolution are equal when the 'vtk.vtkCylinderSource()` is created.)
It seems that the CT value obtained by "bone density measurement at the pedicle screw surface" is also based on the (vtkPolyData) points on the model. For example, a cross section circle (regular hexagon) has only 6 points. No matter how large the diameter is, are only 6 points taken?
You can use Surface Toolbox uniform remesh feature to ensure that the points are representative for the entire screw surface.
You can compute the sum by multiplying the average value by the number of points. However, this will not be representative of the fixation strength. Multiplying by the surface area may be more meaningful. However, you cannot ignore the distribution of the bone density (very high density in one region cannot compensate for lack of density in another region), so probably you need a metric that evaluates the density along the length of the screw (as it is done in Pedicle Screw Planner extension).