Th Golden Age

Professor Henry Ross was a scientist that was working on a project that would give immortality through a radium serum. Convinced he had a break through, Ross experimented on himself by committing suicide and then being injected with the serum. The test was successful, Ross died and was the successfully resurrected, but there were unforeseen consequences. Ross became a human radium ray, whose very presence could irradiate and kill. After accidentally killing one of his colleagues, Ross discovered a way to reduce the radium in his blood unfortunately the antidote required Volitell a very expensive drug, so Ross donned a radiation suit and began robbing various pharmaceutical suppliers in Gotham and ran a foul of Batman and Robin. Believing himself cured, Ross accidentally kills his girlfriend Mary Lamont. Going insane from guilt and the radium, Professor Radium finds himself in a life or death battle with Batman and Robin.

Modern Age

Infinite Crisis

Ross seemingly drowned in his first appearance, but has returned recently and is revealed to have joined a subgroup of the villainous Society known as the Nuclear Legion. The Nuclear Legion is made up of Professor Radium, Reactron, Neutron, Nuclear, Geiger, and Mister Nitro. The team team was sent to Bludhaven to discern the chemical leak.

New 52

While Henry Ross has not appeared in the New 52, Hugh Marder, a new adversary for Batman, has been scene wearing a similar costume to Professor Radium (though he has not adopted that name).