Nerf Radium

[Spy_Guy]

A thought: Cap the maximum amount of rads radium can inflict. That is, it can push you up to 10 rads but won't go higher. Just lowering the amount of rads it inflicts per cycle would work too, but the primary nastiness of radium is that by the time you realize you're poisoned and dying the rads have scaled to the point where you die rapidly, and lowering the rate at which it reaches that point is less helpful. Keeping radium alone from triggering the nastiest of rad effects would limit its effectiveness. Plus it can take quite a while to purge a 100u splash from someone's system.

Most of the other suggested solutions have other consequences, primarily to polonium and the radbow. Those should still be deadly; making pentetic or potassium iodide, or other anti-rad chems better/easier would nerf those as well.