In this paper, the popular FBP algorithm is revisited using discrete tomography. More precisely, our version of the discrete exact Radon (inverse) transform called the Mojette transform is used to model the discrete geometry into which are mapped the initial data. This allows for an exact backprojector definition that is then mixed with the spline-FBP algorithm [2] to produce a novel Mojette-FBP scheme. Adequation to practical geometries used in 3D medical imaging as 3D-PET is presented.