Radiation Shielding Information and Guidance

1. Radiation Shielding Information and Guidance Don Parry, CHP District Health Physicist Michigan Department of Consumer & Industry Services Radiation Safety Section dparry@michigan.gov

2. Regulations and Standards Regarding Plan Reviews • Michigan’s first rules on ionizing radiation were published in February of 1958; Radiation shielding requirements were listed in an appendix based on NBS Handbook 76 • Ionizing Radiation Rules were modified in 1965 and more clearly indicated that: Shielding shall be approved by the Michigan Department of Health • Rule 331(2) of the current Ionizing Radiation Rules (Promulgated in 1975) states that shielding is subject to design approval by the department • Plan reviews have been done routinely by the State Radiation Control Program since 1958 Radiation Safety Section

3. Radiation Shielding Information • Form BHS/HFS 852 – Information Required for a Radiation Shielding Plan Review • Available on Web site at: • www.michigan.gov/bhs (click on Mammography and X-ray Machines – Radiation Shielding Guidance) • Web Site includes guidance on shielding: • Radiographic or RF rooms • Mammography Rooms • Computed Tomography Rooms • Linear Accelerator Vaults • Additional Guidance Radiation Safety Section

4. Radiation Shielding Information • Form BHS/HFS 852 – Information Required for a Radiation Shielding Plan Review • Be sure to include all requested information including: • Plans or blueprints of rooms and adjacent areas to scale with compass directions. (1/4” = 1 foot preferred) • Location of x-ray equipment, x-ray table,wall bucky, exposure switch, viewing window and control panel • Description of occupancy of adjoining areas including above or below • Description of floor and ceiling construction including minimum concrete thickness and density. Radiation Safety Section

5. Radiation Shielding Information • Form BHS/HFS 852 (Continued) • Be sure to include all requested information including: • Location,type, thickness and height of proposed shielding • Indicate thickness and density of concrete and masonry materials • Limits of travel of table, tube and image receptor • Maximum kVp, mA and estimated workload in mAmin/wk • For CT scanners, include a copy of the iso-exposure curves normally provided by the manufacturer • Name and address of facility • Name and address to send response letter Radiation Safety Section

6. Radiation Shielding Information • Plan Reviews • Plans should be submitted prior to construction! • Construction of an x-ray room without an approved plan may cause shielding modifications to be done after the room is constructed Radiation Safety Section

7. Radiation Shielding Information • Certificate of Need • Equipment that requires a CON will not be registered until plans have been reviewed by the Radiation Safety Section. Radiation Safety Section

8. Radiation Shielding Information • Shielding Guidance • Most medical x-ray rooms should normally be provided with 1/8 inch thick lead for primary barriers (including floors) and 1/16 inch thick lead for secondary barriers (including doors) • Vertical barriers must extend from the floor to a minimum height of 7 feet. • If it is necessary to add additional shielding to the ceiling of the room, then the shielding in the walls must be extended above the 7-foot height to overlap the ceiling shielding. Radiation Safety Section

9. Radiation Shielding Information • Shielding Guidance • If there are multi story buildings in close proximity of the x-ray room, which have occupied spaces that could be exposed to scatter radiation that is not attenuated by the 7-foot high wall shielding, additional shielding may be necessary to protect those areas • Outside walls and, particularly, windows may require shielding to protect distant areas even if the nearest occupied area is not immediately adjacent Radiation Safety Section

10. Radiation Shielding Information • Examples • No Occupancy above or below • On Slab • Shielding should be floor to 7’ • 1/16 inch thick secondary, 1/8 inch thick primary 1/8 inch lead (blue) Leakage Scatter 1/16 inch lead (red) Radiation Safety Section

11. Radiation Shielding Information Examples CT with adjacent Multi Story Building May need additional shielding on outside wall Occupied uncontrolled space in adjacent building Adjacent Multi Story Building Radiation Safety Section

12. Radiation Shielding Information Floors Need to use minimum thickness of concrete floor in shielding calculations Need to know density of concrete (147 lbs/ft3 standard) Radiation Safety Section

13. Radiation Shielding Information Examples Occupied space below Need 1/16 inch thick lead on floor with 1/8 thick lead under table Floor shielding should overlap wall shielding Radiation Safety Section

14. Radiation Shielding Information Examples Exposure switch location Switch needs to be arms length from first scattered and leakage radiation Switch Location Adjacent Multi Story Building Radiation Safety Section

15. Radiation Shielding Information • Summary • Submit shielding plans to the Radiation Safety Section for design approval prior to construction! • Include all information requested on form BHS/HFS 852. • Equipment that requires a Certificate of Need will not be registered until a plan is reviewed • Most rooms will be adequately shielded with 1/8 inch thick lead for primary barriers and 1/16 inch thick lead for secondary barriers. • Be sure to consider areas above and below the x-ray room when designing shielding. Radiation Safety Section

16. Contact Information Headquarters:Radiation Safety SectionMichigan Department of Consumer & Industry ServicesP.O. Box 30664Lansing, Michigan 48909 Phone: (517) 241-1989Fax: (517) 241-1981 Visitor/delivery address:5th Floor, G. Mennen Williams Building525 W. Ottawa StreetLansing, Michigan 48933 District Office:Our district office, formerly in Pontiac, has moved to: Radiation Safety SectionMichigan Department of Consumer & Industry Services38600 Van Dyke, Suite 375Sterling Heights, Michigan 48312 Phone: (586) 446-0200Fax: (586) 446-0227 Radiation Safety Section