<prompt> An alternate to lead in the walls of radiology room is:Walls made up of 3 inch concreteWalls made up of barium plaster or barium concreteWalls made up of 3 inch steelAll of the above  <response>: Walls made of 3 concrete, 3 x 16 of steel or 1 mm of lead, barium plaster or barium concrete will suffice to protect adjacent rooms from radiation. 