A certified professional radiation health physicist must calculate the proper amount of lead shielding required based on certain considerations. It will depend on the source of radiation—the type of machine used and where it is located. The following information helps in understanding what factors determine lead shield requirements for diagnostic imagining and radiation therapy. The goal is to ensure that the maximum radiation protection is achieved.
Lead shielding requirements are calculated and determined based on the following considerations:
- Energy potential: The energy potential of the machine will determine the lead shielding requirement—the higher the output of the machine, the higher the lead shielding required.
- Workload: The exposure per week, month or year must be determined, as well as the maximum patient volume growth, as radiation is cumulative and overexposure causes biological damage on the cellular level. Check the local governing health and safety law and codes for current compliance requirements.
- Orientation/Direction: Wall lead shielding is calculated by a physicist in relation to the primary beam target. The direction where the radiation is aimed and will scatter.
- Distance: Radiation will dissipate more as distance increases. The closer a partition is to the radiation/x-ray source, the higher the shielding requirement.
- Occupancy: A very important part in your calculation is the amount of time, per day, a surrounding room similar to the x-ray room (source or radiation) will be occupied by personnel or public. The lead shielding on wall and floors increases with the level of occupancy.
- Type of material: The type of construction material used for wall, partition and floor may reduce the requirement for lead shielding. Heavy density materials such as concrete, steel and plaster can shield radiation to some level.
All lead shielding requirements should be calculated by an expert.