2A12B Shielding Design Cath Lab.pdf

Radiation Shielding Design Calculations March 21st, 2018 Facility X-Ray Room XX

Radiation Shielding Design

CATH LAB 2A12B

10/3/2022

VA CENTRAL CALIFORNIA

2615 E. CLINTON AVE.

FRESNO, CA 93703

Jeremy L. Corwin, MHP, DABHP Medical Physicist jeremy@corwinhp.com mailto:jeremy@corwinhp.com

Radiation Shielding Design Calculations October 3rd, 2022 VA Central California - Fresno, CA X-Ray Room 2A02B

Shielding Design Summary

Shielding calculations were performed for the fluoroscopic system that will be installed in Cath Lab 2A12B at VA Central California in Fresno, California.

A summary table of shielding calculations is at enclosure 1. An annotated floorplan with shielding requirements is at enclosure 2. The following is a detailed explanation of the required shielding on each wall.

Outline of Required Shielding

The following shielding specifications are the minimum amount of shielding required to reduce radiation exposures to below the current regulatory limits. Installation of shielding that is thicker than specified below is acceptable. All wall shielding must extend from floor to ceiling unless otherwise noted.

Control Wall / Window - Wall A. The Control Wall / Window requires 1.58 mm lead shielding extending from the floor to the ceiling.

Hallway Wall / Doors - Wall B. The Hallway Wall / Doors require 1.58 mm lead shielding.

Note: The specified amount of shielding will adequately shield the hallway as well as the higher occupied work room beyond. The Hallway Wall shielding must extend from the floor to a minimum height of 7' 0".

Bathroom Wall - Wall C. The Bathroom Wall requires 0.79 mm lead shielding.

Note: The Bathroom Wall shielding must extend from the floor to a minimum height of 7' 0".

Exterior Wall - Wall D. The Exterior Wall does not require additional shielding. The existing 12” of concrete (≈ 304 mm total) will provide adequate shielding.

System Component Wall - Wall E. The System Component Wall requires 1.58 mm lead shielding extending from the floor to the ceiling.

Note: The specified amount of shielding will adequately shield the system component room as well as the higher occupied office beyond.

Storage Walls - Wall F. The Storage Walls require 1.58 mm lead shielding extending from the floor to the ceiling.

Note: The specified amount of shielding will adequately shield the storage rooms as well as the higher occupied MRI Zone 2 beyond.

Floor: The four inch concrete deck is not adequate. The Floor requires an additional

0.79 mm lead shielding.

Ceiling: The four inch concrete deck is not adequate. The Ceiling requires an additional

0.79 mm lead shielding.

Methods and Assumptions

The shielding requirements above were based on the following information:

The proposed x-ray system is a Philips Azurion 7 C20 FlexArm Stationary C-Arm system.

For the purpose of shielding calculations, the maximum allowable exposure limit for controlled areas is 0.10 mGy/week while the limit for uncontrolled areas is 0.02 mGy/week.

The maximum workload of 6 patients per 8 hours was provided by the facility. The provided workload was modified for a 40 hour work week to make 30 patients/week.

This modified workload was used for the shielding calculations.

The occupancies of surrounding areas are noted on the enclosed summary table of shielding calculations and the annotated floorplan.

The primary reference for these shielding calculations is NCRP Report 147, Structural Shielding Design for Medical X-Ray Imaging Facilities.

Please note the following:

These shielding recommendations are based on information provided by the facility at the time of this shielding design. If changes occur regarding the occupancy of surrounding areas, the type of x-ray system being used, or an increase in workload, additional shielding may be required.

California Radiation Control Regulations require that all x-ray machines be registered with the State of California, Department of Public Health. The Radiation Machine Registration can be completed online by following the link below.

https://cdph-rhb.powerappsportals.us/

It is believed that Los Angeles County and San Diego County are the only counties that require submission of shielding designs to their respective health departments.

Please check with your local county health department to determine if shield design plans need to be submitted for approval before construction begins.

https://cdph-rhb.powerappsportals.us/

Please keep a copy of this shielding plan at your facility indefinitely.

Thank you for allowing us to perform your shielding calculations. If you have any questions, please call me at (360) 736-6066.

Jeremy L. Corwin, MHP, DABHP Medical Physicist

CORWIN HEALTH PHYSICS INC

Enclosures:

Summary of Shielding Calculations Annotated Floorplan Appendix A - Recommendations for Shielding Penetrations Appendix B - Schedule of Commercial Lead Shielding

Average kVp Patients Per Week mA-min/Patient Other Total

Philips Azurion 7 C20 FlexArm Cath Lab 2A12B See NCRP 147 30 160 0 4800

Wall Wall Primary or Type of Occupancy Distance to Description Description Secondary Occupancy Factor Occupied Area (m) Thickness (mm) Type

Control Wall / Window A Secondary Controlled 1 3.81 0.84 Lead

Hallway Wall / Doors B Secondary Uncontrolled 1 9.14 0.80 Lead

Bathroom Wall C Secondary Uncontrolled 1/20 6.55 0.20 Lead

Exterior Wall D Secondary Uncontrolled 1/40 3.35 28.89 Concrete

System Component Wall E Secondary Uncontrolled 1 6.86 1.00 Lead

Storage Wall F Secondary Uncontrolled 1 7.16 0.97 Lead

Floor N/A Secondary Uncontrolled 1 3.35 107.85 Concrete

Ceiling N/A Secondary Uncontrolled 1 3.20 110.17 Concrete

Notes:

All wall shielding must extend from floor to ceiling unless otherwise noted.

1The specified amount of shielding will adequately shield the hallway as well as the higher occupied work room beyond.

2The Hallway Wall shielding must extend from the floor to a minimum height of 7' 0".

3The Bathroom Wall shielding must extend from the floor to a minimum height of 7' 0".

4The specified amount of shielding will adequately shield the system component room as well as the higher occupied office beyond.

5The specified amount of shielding will adequately shield the storage rooms as well as the higher occupied MRI Zone 2 beyond.

The mA-min/patient listed above is the designated workload from NCRP Report No. 147 for Cardiac Angiography.

Shielding Specifications Calculated

Existing Shielding Required ShieldingShielding

28 mm GWB 1.58 mm Lead

1.58 mm Lead5

28 mm GWB 0.79 mm Lead3

304 mm Concrete None

28 mm GWB 1.58 mm Lead1,2

101 mm Concrete 0.79 mm Lead

28 mm GWB 1.58 mm Lead4

28 mm GWB 101 mm Concrete 0.79 mm Lead

Type of X-Ray Machine Room ID Workload Information

(mA-Minutes/week)

Summary of Shielding Calculations VA Central California - Fresno, CA

Cath Lab 2A12B October 3rd, 2022

Hallway

Control Area

Hallway

Exterior

Bathroom

Control Wall / Window - Wall A.

The Control Wall / Window requires

1.58 mm lead shielding.

Floor and Ceiling: The Floor and Ceiling both require 0.79 mm lead shielding.

0.79 mm Lead Placement

1.58 mm Lead Placement

0.79 mm Lead Placement in Floor and Ceiling

System Component Wall - Wall E.

The System Component Wall requires 1.58 mm lead shielding.

Storage Walls - Wall F.

The Storage Walls require

1.58 mm lead shielding.

Exterior Wall - Wall D.

The Exterior Wall does not require additional shielding.

The existing 12” of concrete ( 304 mm total) will provide adequate shielding.

Hallway Wall / Doors - Wall B.

The Hallway Wall / Doors require

1.58 mm lead shielding.

Note: The Hallway Wall shielding must extend from the floor to a minimum height of 7' 0".

Bathroom Wall - Wall C.

The Bathroom Wall requires

0.79 mm lead shielding.

Note: The Bathroom Wall shielding must extend from the floor to a minimum height of 7' 0".

Appendix A – Recommendations for Shielding Penetrations

Shielding Screw/Nails: Penetrations made by screws/nails do not require lead “tabs” to cover the top of the screws/nails. The steel nails/screws generally attenuate radiation equally, or more effectively than the lead displaced by the screws/nails.

Shielding Joints: The joints between lead sheets should be constructed so that their surfaces are in contact with an overlap of not less than 1 cm. This can be accomplished by using lead battens, or by using drywall that is manufactured with the lead sheet extending beyond the edge of the drywall for adequate overlap.

Shielding Penetrations: Air conditioning ducts, electrical conduit, plumbing, and other infrastructure will penetrate shielded walls, floors, and ceilings. The shielding of the x-ray room shall be so constructed that the protection is not impaired by these openings or by service boxes, etc., embedded in barriers. The duct/conduit shielding thickness shall be equivalent to the displaced shielding thickness. Below are general shielding details for duct/pipe penetrations into a shielded surface where H is the diameter of the penetration.

1. Straight pipe/conduit penetration: Situations where there is a straight pipe/conduit penetrating a lead shielded surface require lead to line (wrap) the pipe/conduit twice the distance as the diameter/thickness of the pipe or conduit. See Detail 1 below.

Detail 1:

2. Curved elbow penetration: Situations where there is a curved pipe/conduit penetrating lead shielding requires lead to line (wrap) to line the entire top/backside of the elbow and pipe for 3 times the distance of the diameter of the opening. See Detail 2 below.

Detail 2:

3. Flat Panel Penetrations (electrical panels etc.). Flat panel penetrations can be shielded by either wrapping the entire structure (panel/box) being installed or by shielding behind the panel/box. If the lead shielding is installed behind the panel, the lead must extend beyond each side of the panel (penetration) by twice the thickness of the wall. For example, if the wall is 4 inches thick, the lead shielding must extend 8 inches beyond each edge of the cut-out section of the wall.

4. 90 degree elbow running out of the wall: Situations where there is a 90 degree elbow penetrating a lead shielded surface requires lead to line the top of the elbow up to the 90 degree turn, and then the back side of the pipe for twice the distance of the diameter/thickness of the pipe PLUS the thickness of the wall. See Detail 3 below:

Detail 3:

The above recommendations and details are adequate for shielding most common shielding penetrations. There may be exceptions where these methods are not appropriate for providing adequate radiation protection. Please contact Corwin Health Physics if there are other questions on how to appropriately shield a space.

Reference: The primary reference for these recommendations is NCRP Report 147.

Appendix B – Schedule of Commercial Lead Shielding

Thickness (mm)

Thickness (inches)

Weight in Pounds per Square Foot (PSF)

0.79 1/32 2

1.00 5/128 2.5

1.19 3/64 3

1.58 1/16 4

1.98 5/64 5

2.38 3/32 6

3.00 -- 7.5

3.17 1/8 8

3.97 5/32 10

4.76 3/16 12

5.55 7/32 13

6.35 1/4 16

8.47 1/3 20

9.52 3/8 24

12.70 1/2 30

19.05 3/4 45

25.40 1 60