  The inverse scattering problem of the reconstruction of the unknown potential
with compact support in the 3-d Schr\"odinger equation is considered. Only the
modulus of the scattering complex valued wave field is known, whereas the phase
is unknown. It is shown that the unknown potential can be reconstructed via the
inverse Radon transform. Therefore, a long standing problem posed in 1977 by K.
Chadan and P.C. Sabatier in their book "Inverse Problems in Quantum Scattering
Theory" is solved.
