A process for treating highly localized carcinoma cells that provides precise positioning of a therapeutic source of highly ionizing but weakly penetrating radiation, which can be shaped so that it irradiates essentially only the volume of the tumor. The intensity and duration of the radiation produced by the source can be activated and deactivated by controlling the neutron flux generated by an array of electrically controlled neutron generators positioned outside the body being treated. The energy of the neutrons that interact with the source element can be adjusted to optimize the reaction rate of the ionized radiation production by utilizing neutron moderating material between the neutron generator array and the body. The source device may be left in place and reactivated as needed to ensure the tumor is eradicated without exposing the patient to any additional radiation between treatments. The source device may be removed once treatment is completed.
