<prompt> Direct action of radiation is the dominant process forX-raysNeutrons and alpha paiclesElectronsGamma rays  <response>: Ionizing radiation acts by two methods: Direct and IndirectDirect action is radiation directly causing DNA damage; example: neutrons and alpha paiclesIndirect action is radiation causing free radical production which acts on DNA; example: photons and gamma raysReference: Khan Physics of Radiation therapy; 5th edition 