Walls of the CT scanner room are coated with:
Shielding refers to use of any type of material to decrease radiation that reaches an area. The material most commonly used is lead, such as lead-lined gloves and lead aprons. Other materials such as concrete walls are capable of shielding. Ref: Essentials of Nursing : Care of Adults and Children By Barbara Kuhn Timby, Nancy Ellen Smith, Page 278
Lead
Glass
Tungsten
Iron