Advanced radiation suit (Fallout 3)

The advanced radiation suit is a suit specially designed to stop radiation better than the standard radiation suit, meaning it has the highest amount of radiation resistance of any armor in the game. It covers the entire body. As such, it is impossible to wear a helmet or glasses with this armor, except the biker goggles.

Locations
It can be found deep within Vault 87, in the Test Labs. When you get to the room with the Lab Technician's terminal (on a desk to the right) one of the options will be to unlock the storage room. Choose that option, then turn around and go back out the door you entered and turn left. That door is the storage room and contains the Advanced Radiation Suit.

Another may be found in the Franklin Metro Utility, in a box titled "Radiation Suit Case", at the bottom of a flooded tunnel.

One can also be found in Point Lookout, inside a muck hole during An Antique Land.

Another 2 are in Mothership Zeta, in the operating room in the Cryo Labs, on a table.

Can also be bought from Moira at Craterside Supply, Gustavo or Michael Masters from Tenpenny Tower, Karl at Meresti Metro Station, Tulip in the Underworld, Flak 'N Shrapnel's in Rivet City, Crow if you invest the maximum amount into his inventory and Knight Captain Durga in the Citadel if you get permission to trade.

Appearances
The advanced radiation suit appears only in Fallout 3 and Fallout: New Vegas.