The invention comprises an apparatus and method of use thereof for extracting ions from an ion source, such as for use in cancer treatment or tomographic imaging. The extraction apparatus uses a triode extraction system, with the ion source and/or first electrode held at a first potential; an extraction electrode held at a second potential; and a gating electrode, positioned between the ion source and the extraction electrode, oscillating and/or alternating between a first suppression potential proximate that of the ion source potential and a second extraction potential between the ion source potential and the extraction electrode potential. Optionally, the ion source comprises an electron cyclotron resonance ion source.