Minnesota Department of Health rules have many requirements around construction and use of facilities to keep dose limits to operators of x-ray units, and members of the general public in surrounding areas, at or below regulatory limits. Depending on the type of x-ray unit, these regulations may require that a shielding plan be developed and submitted to MDH prior to construction or installation of the unit.
After construction and installation of the x-ray unit, an exposure rate survey must be conducted to verify that the shielding design and construction provides adequate protection. In most cases, this will require access to surrounding areas, in others, a survey around a self-shielded unit is sufficient. Any changes to the unit that could change radiation output or alter the shielding of the unit, and any changes to the space, will require a new survey.
In summary, you will need a shielding plan for:
- New Facility
- Modification of shielding in an existing x-ray room (with or without previous shielding present)
- Change in equipment type or output
- EXEMPTIONS: Bone densitometry, mammography, dental intraoral, and some analytical research units
Whenever the addition of radiation producing equipment is planned, it is important to contact the Department of Radiation Safety (DRS) as soon as possible in the process to ensure all requirements are met.
Important information required to complete a shielding plan:
- Type and output characteristics of the x-ray unit
- Make and model of the x-ray unit
- Workload – average number of exam subjects per day/week/month
- Facility characteristics – floorplans with room dimensions, description of materials used in walls, placement of the x-ray unit, and a description of the adjacent spaces
- The proposed timing of the project
Shielding plans must be completed by a qualified Health or Medical Physicists. The Department of Radiation Safety, the Department of Radiology, and many outside vendors offer this service. Please contact DRS at (612) 626-6002 or email [email protected] to review the shielding plan options for your specific facility and to arrange for a post-installation shielding verification survey.