When diagnostic rooms require lead shielding, most often there is a report prepared by a radiation shielding physicist instructing how much lead is needed and where it is needed. It contains the official requirements for lead lining diagnostic rooms such as X-Ray, CT, Fluoroscopy, etc. Most states will require this report if radiation is going to be present, and that report should be on file with the facility and with the state as well. Not all states have the same requirements. It is ultimately up to the facility owners to know their state requirements and to make sure these studies are done prior to construction. The report keeps an owner from spending too much money trying to guess how much lead is required and over-shielding. It also keeps an owner from being in a position where there is not enough lead protection, which can result in radiation exposure to others in the facility.
Ideally, the physicist’s report (also called a shielding report) is part of the specifications for a medical project that will require lead lined materials. Sometimes the report is not available before the project documents are compiled. When looking for a qualified radiation shielding physicist, facility owners and architects may find a local company or individual whose only job is working on shielding designs. They also may consult with a larger local hospital. Larger facilities usually have a physicist who does regular work for them or a radiation shielding physicist on staff.
Typically, a physicist’s report will list the room(s) being shielded, the amount of lead required for each wall and component of each wall and the lead height requirement. The report will also indicate what lead, if any, is needed to shield a room’s floor and ceiling. Many physicists will include a sketch of the room. Walls will be labeled with letters or numbers, and the report will list the requirements per each wall or section of wall with a corresponding chart. An example of this is shown below
The format of this report is arranged in the following manner:
1. A summary of the shielding design in general.
2. The design for a specific room followed by the floor plan for that room.
3. In conclusion, the general design criteria is detailed.
Shielding is required to protect those persons working adjacent to x-ray rooms. Lead which offers special shielding properties at medical x-ray energies is the preferred and most used material.
All diagnostic shielding walls require the shielding to extend from the floor to at least 7 feet above the floor. The doors and windows in them are required to be of equivalent shielding in all cases. That is, when a wall requires 1/16 inch lead shielding, a door or window installed in that wall is also required to have shielding equivalent to 1/16 inch of lead. Particular attention must be given to the construction of all joints and where penetrations occur.
Floors and Ceilings
In this design, there is no occupancy above the ceiling or below the floor; therefore, the usual construction materials provide adequate shielding so that no additional lead is required in the floors and ceilings.
The control booth is designed to maximize the protection of the operator while providing the operator the most advantageous view of the room. In all cases, the control switch must be positioned at least 40 inches from the outside edge of the control booth.
CT Shielding Design Data
|FACILITY: Local Community Hospital||DATE: February 15, 2015|
123 Hospital Street
Rome, GA 30161
123 Hospital Street
Rome, GA 30161
|ROOM: CT Scan||GENERATOR: GE Optima CT600|
AVERAGE mAs/patient: 4500
|WORK LOAD (patients/wk): 100|
|SLICE THICKNESS (mm): 40||(mAs/week): 450,000|
This is one example of how a physicist report appears. There are several variations. In this example, the lead thickness requirements are listed in inches. Sometimes they are listed in millimeters and other times they are listed in pounds per square foot.
If A&L Shielding has a shielding report for review and information in the report conflicts with requirements listed in other contract documents, we will quote per the report and qualify our bid. This is because the shielding design is the official document of record where lead lining is concerned.