The present invention concerns a method and a medical apparatus for visualizing a hadron beam traversing an organic body, said method comprising capturing a magnetic resonance image wherein a volume of irradiated excitable atoms A1, surrounding a hadron beam and whose magnetic susceptibility has been modified by said hadron beam is captured as a hyposignal. A hyposignal is obtained by saturating the spins of the irradiated excitable atoms A1, before capturing a MR image based on the excitation of the excitable atoms A0 which are not affected by the hadron beam.
