Proton TherapyProtonsRadiotherapy Planning, Computer-AssistedRadiotherapy DosageRadiotherapy, Intensity-ModulatedOrgans at RiskRadiometryCraniospinal IrradiationNeutronsChordomaMonte Carlo MethodProton PumpsPhotonsRadiotherapy, ConformalRadiotherapy, High-EnergyRelative Biological EffectivenessRadiation InjuriesUncertaintyFour-Dimensional Computed TomographyScattering, RadiationRadiation DosagePhantoms, ImagingRadiation OncologyFibromatosis, AbdominalRadiotherapyRadiotherapy, Computer-AssistedProton Pump InhibitorsDose-Response Relationship, RadiationTumor BurdenTomography, X-Ray ComputedProstatic NeoplasmsAlgorithmsTreatment OutcomeNeoplasms, Radiation-InducedMagnetic Resonance SpectroscopyHydrogen-Ion ConcentrationMovementSpineReproducibility of Results