Assembly for irradiating patients with charged particles, having a raster scanning - irradiation unit which has a particle accelerator, a beam guiding unit and a 3D scanning system, wherein the 3D scanning system has an energy variation unit to adjust the energy of the particle beam and thus the penetration depth of the beam in the patient in the beam direction and a deflection unit having a plurality of deflecting magnets (18, 20) for two-dimensional deflection of the beam between individual raster points in each layer, defined by the energy variation unit and arranged transversely to the beam direction, of predetermined penetration depth in the patient, a treatment planning system for generating treatment planning data which comprise the energy derived from the desired dose distribution and number of charged particles for each raster point in each layer, a treatment control system which converts the treatment planning data generated by the treatment planning system into irradiation data and irradiation commands (44, 52) for the particle accelerator, the beam guiding unit and the 3D scanning system, and a plurality of safety means (34, 48, 56) to check the correct implementation of the treatment planning data and the functionality of the assembly, wherein the plurality of safety means (34, 48, 56) comprise an evaluation unit which checks the irradiation data and irradiation commands supplied by the treatment control system to the 3D scanning system, characterised in that the evaluation unit is suited to check the irradiation data and irradiation commands supplied by the treatment control system to the 3D scanning system for their treatment-specific plausibility, in that a) the evaluation unit checks the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility with regard to permitted energy ranges of the charged particles; and / or in that b) the raster scanning - irradiation unit has a rotating gantry and the evaluation unit checks the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility with regard to permitted gantry angles for the application of the charged particles; and / or in that c) the evaluation unit checks the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility with regard to the number of charged particles to be applied for each raster point; and / or in that d) the evaluation unit examines the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility in relation to predetermined logical ordering principles, wherein dl) the evaluation unit checks the strictly decreasing monotony of the energy values of the charged particles to be applied to check the decreasing penetration depth between the individual layers to be crossed during scanning; and / or wherein d2) the evaluation unit checks the sequence and arrangement of the raster points for each layer to be crossed during scanning. a) the evaluation unit checks the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility with regard to permitted energy ranges of the charged particles; and / or in that b) the raster scanning - irradiation unit has a rotating gantry and the evaluation unit checks the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility with regard to permitted gantry angles for the application of the charged particles; and / or in that c) the evaluation unit checks the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility with regard to the number of charged particles to be applied for each raster point; and / or in that d) the evaluation unit examines the irradiation data and irradiation commands generated by the treatment control system for their treatment-specific plausibility in relation to predetermined logical ordering principles, wherein dl) the evaluation unit checks the strictly decreasing monotony of the energy values of the charged particles to be applied to check the decreasing penetration depth between the individual layers to be crossed during scanning; and / or wherein d2) the evaluation unit checks the sequence and arrangement of the raster points for each layer to be crossed during scanning. dl) the evaluation unit checks the strictly decreasing monotony of the energy values of the charged particles to be applied to check the decreasing penetration depth between the individual layers to be crossed during scanning; and / or wherein d2) the evaluation unit checks the sequence and arrangement of the raster points for each layer to be crossed during scanning.