Radon transform and parton distributions

The Radon transform (RT), being best known for its applications to computer tomography, is discussed is some detail. There is a more recent application to the non-perturbative QCD matrix elements, related to Generalized Parton Distributions. RT provides a complementary view to crossing and analytic properties of hard exclusive amplitudes. It also allows one to derive holographic sum rules reducing the effective dimension of parameters space in the description of various processes. The case of diffractive parton distributions is also considered.