Factors related to the design thickness of the lead plate and the protective layer: 1. The tube voltage and the tube current of the X-ray machine are too small 2. The distance between the protective layer and the X-ray machine target (ball tube) 3. The type of the X-ray machine Whether it is a machine or a weekly machine, 4. The length of time the operator spends working each week, 5. The influence of environmental factors, whether there is a person working or moving outside the inspection site to determine if there is a need for a local increase or decrease. Properties, generally high density materials have good protective effect. Such as lead, steel, concrete, lead glass and so on.