663-CSI-021 - Shielding Design - Specials C-Arm Rm 2D-117 .pdf

Radiation Shielding Design Calculations April 15th, 2022 VA Puget Sound Health Care System Special Procedures 2D-117

Radiation Shield Design

SPECIAL PROCEDURES

(ROOM 2D-117)

4/15/2022

VA PUGET SOUND HEALTH CARE SYSTEM

1660 S COLUMBIAN WAY

SEATTLE WA, 98108

Jeremy L. Corwin, MHP, DABHP Medical Physicist

Jeremy@corwinhp.com

Shielding Design Summary

Shielding calculations were performed for a new Specials Procedures Artis Q C-Arm system being installed at VA Puget Sound Health Care System in Seattle Washington.

A summary chart of the required shielding is at enclosure 1. A scale drawing of the room is at enclosure 2.

Summary of Required Shielding

The following lead shielding is the minimum amount of lead required to reduce radiation exposures to below the current regulatory limits. Installation of lead thickness greater than those specified below is acceptable. Unless noted, all lead must extend from the floor to a height of 7 feet.

Please Note: Core samples were provided by the facility. It is assumed that each sample represents its respective wall and that the existing shielding covers the entire wall from the floor to a height of 7 feet.

Control Wall, Window and Door - Wall A. The existing 1.19 mm lead shielding provides adequate protection along the Control Wall, Window and Door. Please note: the shielding for the door was not provided, it must contain at least 1.19 mm lead. Please verify and add if necessary. Also note: the core sample for the area adjacent to the door (see attached floor plan) showed no shielding was present. Ensure at least 1.19 mm lead is installed in this wall.

Special Procedures 2D-115 - Wall B. A core sample was not provided for the wall between special procedure rooms. This wall requires at least 1.00 mm lead. Please verify and install lead if it is not present.

Corridor C2-22 and Door - Wall C. The existing 2.00 mm lead along the Corridor C2- 22 wall provides adequate protection. No additional shielding along the wall is required.

Please note: the shielding for the door into the corridor was not provided. Please ensure the door has at least 0.79 mm lead shielding. If not, install a 0.79 mm lead door.

Corridor C2-36 - Wall D. The existing 2.00 mm lead along the Corridor C2-36 wall provides adequate protection. No additional shielding is required.

Restroom 2D-123 - Wall E. The existing 1.19 mm lead along the Restroom 2D-123 wall provides adequate protection. No additional shielding is required.

Viewing C2-26 - Wall F. The existing 1.19 mm lead along the Viewing C2-26 wall provides adequate protection. No additional shielding is required.

Floor: The existing 4.5" concrete provides adequate protection along the Floor. No additional shielding is required.

Ceiling: The existing 4.5" concrete provides adequate protection along the Ceiling. No additional shielding is required.

Methods and Assumptions

The above shielding recommendations were based on the following information:

The x-ray system is a Artis Q fixed c-arm system.

The maximum weekly exposure rates for controlled areas is 0.10 mGy per week and for uncontrolled areas is 0.02 mGy/week.

The estimated workload noted in the summary charts is based on a maximum of 48 patients per week. The NCRP 147 standard of 160 mA/min per patient was used in these calculations.

The image receptor for the fluoroscopic system was considered the primary barrier.

The occupancy of each room was determined from input from the facility and is noted on the enclosed detailed summary sheet and diagram.

The existing construction of the floors and ceiling was determined by documents provided by the architect and project managers. If the existing shielding or construction is found to differ from that noted in the enclosed charts, additional shielding may be required.

This shielding design was conducted in accordance with NCRP 147, Structural Shielding Design for Medical X-Ray Imaging Facilities, January 2005.

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 jeremy@corwinhp.com

CORWIN HEALTH PHYSICS INC

Enclosures:

Shielding Summary Diagram of Room Appendix A – Shielding Penetration Guidelines Appendix B – Schedule of Commercial Lead Shielding

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

Artis Q Specials C-Arm 2D-117 See NCRP 147 48 160 0 7680

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

Control Wall, Window and Door A Secondary Controlled 1 3.05 1.18 Lead

Special Procedures 2D-115 B Secondary Uncontrolled 1 8.23 1.04 Lead

Corridor C2-22 and Door C Secondary Uncontrolled 1/5 5.49 0.76 Lead

Corridor C2-36 D Secondary Uncontrolled 1/5 3.35 1.10 Lead

Restroom 2D-123 E Secondary Controlled 1/20 3.05 0.27 Lead

Viewing C2-26 F Secondary Controlled 1 4.27 0.93 Lead

Floor N/A Secondary Uncontrolled 1 4.72 58.91 Concrete

Ceiling N/A Secondary Uncontrolled 1 4.70 59.14 Concrete

Notes:

All shielding extends from the floor to a height of seven feet unless otherwise noted.

Please see the detailed report for additional information.

* Wall A. Shielding for the door was not provided. It must contain at least 1.19 mm lead. Please verify and add lead if necessary.

* Wall A. The Core sample for the area adjacent to the door (see diagram) showed no shielding was present. Ensure at least 1.19 mm lead is installed in this portion of wall.

**Wall B. A core sample was not provided for the wall between the two special procedures rooms. This wall requires at least 1.00 mm lead. Please verify and install lead if it is not present ***Wall C. The shielding for the door into the corridor was not provided. Please ensure the door has at least 0.79 mm lead. If not, install a 0.79 mm lead door.

The above mA/min per patient was based on an estimated 60 seconds of fluoroscopy time per patient using a default technique of 3.0 mA.

Shielding Specifications Calculated

Existing Shielding Required ShieldingShielding

2" Steel + 4.5" Concrete None

Unknown **(See Note)

None* (See note)

None

2.00 mm Lead + Door ***(See Note)

2.00 mm Lead None

Summary of Shielding Calculations VA Puget Sound Health Care System

Artis Q C-Arm April 15th, 2022

Please note: Core samples were provided by the facility. It is assumed that each sample represents its respective wall and that the existing shielding covers the entire wall from the floor to a height of 7 feet.

Type of X-Ray Machine Room ID Workload Information

(mA-Minutes/week)

2" Steel + 4.5" Concrete None

1.19 mm Lead None

1.19 mm Lead

1.19 mm Lead + Door

Corridor C2-36 - Wall D. The existing 2.00 mm lead along the Corridor C2-36 wall provides adequate protection. No additional shielding is required.

Floor: The existing 4.5" concrete provides adequate protection along the Floor. No additional shielding is required.

Restroom 2D-123 - Wall E. The existing 1.19 mm lead along the Restroom 2D-123 wall provides adequate protection. No additional shielding is required.

Viewing C2-26 - Wall F. The existing 1.19 mm lead along the Viewing C2-26 wall provides adequate protection. No additional shielding is required.

Special Procedures 2D-115 - Wall B. A core sample was not provided for the wall between special procedure rooms. This wall requires at least 1.00 mm lead. Please verify and install lead if it is not present.

Corridor C2-22 and Door - Wall C. The existing 2.00 mm lead along the Corridor C2-22 wall provides adequate protection. No additional shielding along the wall is required. Please note: the shielding for the door into the corridor was not provided. Please ensure the door has at least 0.79 mm lead shielding. If not, install a 0.79 mm lead door.

Control Wall, Window and Door - Wall A. The existing

1.19 mm lead shielding provides adequate protection along the Control Wall, Window and Door. Please note: the shielding for the door was not provided, it must contain at least 1.19 mm lead. Please verify and add if necessary.

Ceiling: The existing 4.5" concrete provides adequate protection along the Ceiling. No additional shielding is required.

Please note: core sample from this area showed no lead shielding is present. Ensure at least 1.19 mm lead is installed in this wall.

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