Dynamic ridge filter for shaping a dose deposition zone by radiation with charged particles beams, preferably with proton or other light ion beams, and for depositing doses (Dj) applied by pencil beams (Bj) propagating along corresponding irradiation axes (Zj) fanning out of a central irradiation axis by a pencil beam scanning system and delivered in sequence to specific volumes (Vj) along a X-axis to form specific volume stripes distributed next to one another along a Y-axis transverse, preferably normal, to the X-axis, the specific volumes (Vj) defining in combination a target volume (Vt) comprising the tumoral cells, wherein the dynamic ridge filter comprises a number of energy spreading units, each energy spreading unit being characterized by a corresponding energy spreading capacity for spreading the dose deposited along the irradiation axis (Zj) by the corresponding pencil beams (Bj) traversing one or more energy spreading units, Characterized in that, • the energy spreading units are distributed in filter modules, each filter module supporting one or more energy spreading units and having an area normal to the central irradiation axis compatible with a cross-section of the corresponding pencil beam (Bj), wherein the filter modules are arranged in different filter rows, each extending along the row-direction, • each filter row comprises a number of dissimilar filter modules, each filter module of a filter row having a different energy spreading capacity from the other filter modules of the same filter row, wherein ∘ each filter row can be displaced independently to form a filter string along the X-axis and ∘ the filter string is configured to shape the dose deposition in the specific volumes (Vj) forming the specific volume stripe facing the filter string along the irradiation axes (Zj). wherein the dynamic ridge filter comprises a number of energy spreading units, each energy spreading unit being characterized by a corresponding energy spreading capacity for spreading the dose deposited along the irradiation axis (Zj) by the corresponding pencil beams (Bj) traversing one or more energy spreading units, Characterized in that, • the energy spreading units are distributed in filter modules, each filter module supporting one or more energy spreading units and having an area normal to the central irradiation axis compatible with a cross-section of the corresponding pencil beam (Bj), wherein the filter modules are arranged in different filter rows, each extending along the row-direction, • each filter row comprises a number of dissimilar filter modules, each filter module of a filter row having a different energy spreading capacity from the other filter modules of the same filter row, wherein ∘ each filter row can be displaced independently to form a filter string along the X-axis and ∘ the filter string is configured to shape the dose deposition in the specific volumes (Vj) forming the specific volume stripe facing the filter string along the irradiation axes (Zj). • the energy spreading units are distributed in filter modules, each filter module supporting one or more energy spreading units and having an area normal to the central irradiation axis compatible with a cross-section of the corresponding pencil beam (Bj), wherein the filter modules are arranged in different filter rows, each extending along the row-direction, • each filter row comprises a number of dissimilar filter modules, each filter module of a filter row having a different energy spreading capacity from the other filter modules of the same filter row, wherein ∘ each filter row can be displaced independently to form a filter string along the X-axis and ∘ the filter string is configured to shape the dose deposition in the specific volumes (Vj) forming the specific volume stripe facing the filter string along the irradiation axes (Zj). ∘ each filter row can be displaced independently to form a filter string along the X-axis and ∘ the filter string is configured to shape the dose deposition in the specific volumes (Vj) forming the specific volume stripe facing the filter string along the irradiation axes (Zj).