Purpose of Shielding

To protect :

• the x-ray department staff
• the patients (when not being x-rayed)
• visitors and the public
• persons working adjacent to or near the x-ray facility

Radiation Shielding - Design Concepts

Data required include consideration of :

• Type of x-ray equipment
• Usage (workload)
• Positioning
• Whether multiple tubes/receptors are being used
• Primary beam access (vs. scatter only)
• Operator location
• Surrounding areas

Shielding Design (I)

Equipment

What equipment is to be used ?

• General radiography
• Fluoroscopy (with or without radiography)
• Dental (oral or OPG)
• Mammography
• CT

Shielding Design (II)

The type of equipment is very important for the following reasons :

• where the x-ray beam will be directed
• the number and type of procedures performed
• the location of the radiographer (operator)
• the energy (kVp) of the x-rays

Shielding Design (III)

Usage

• Different x-ray equipment have very different usage.
• For example, a dental unit uses low mAs and low (~70) kVp, and takes relatively few x-rays each week
• A CT scanner uses high (~130) kVp, high mAs, and takes very many scans each week.

Shielding Design (IV)

• The total mAs used each week is an indication of the total x-ray dose administered
• The kVp used is also related to dose, but also indicates the penetrating ability of the x-rays
• High kVp and mAs means that more shielding is required.

Shielding Design (V)

Positioning (...Continued on the next post)