Gamma radiation is no more particle radiation in the sense that I used it than is light. True, both are photonic, but photons are conceived as having zero rest mass, and both are thought of primarily as waves.
Electrons have a wave nature, but are considered (beta) particles in everyday usage as they have rest (relativistic) mass, as do alpha particles.
Which has a lot to do with the fact that photons travel at C (no relativistic mass), but 'true' particles approach infinite mass when they try to... or something like that.
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Yes, I know I've missed a few bits out. If you want to post a clarification... fine, just don't force me to post another one.