Some questions about the voxel_backprojection.cu

Regarding the voxel_backprojection.cu function, is the backprojection calculation consistent with the idea in the following text?

For each source and detector position, one calculates the position of the line from the source, through the center of a voxel of interest hits the detector. Then the backprojection at this source and detector position is calculated by bilinear interpolation of where the line described in the previous sentence hits the detector. That's it.