Omega radiation

From Memory Alpha, the free Star Trek reference.

Omega radiation was a type of radiation.

In 2376, the con artist Mobar, pretending to be "Tuvok", informed two Telsian miners that their bolomite could be used for omega radiation therapy. This was most fortunate, as the "Narva colony" had just recently been exposed to omega radiation that killed all the adults, leaving a number of orphans. (VOY: "Live Fast and Prosper")

Based on the source of the term, the credibility of the existence of this type of radiation is left open to interpretation.