An alternate to lead in the walls of radiology room is:
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.
Walls made up of 3 inch concrete
Walls made up of barium plaster or barium concrete
Walls made up of 3 inch steel
All of the above