Analysis of shielding calculation methods for 16- and 64-slice computed tomography facilities

Area of Science:

• Medical Physics
• Radiological Protection
• Diagnostic Imaging

Background:

• New multislice computed tomography (CT) scanners necessitate updated shielding calculation methods.
• NCRP Report No. 147 outlines three shielding calculation approaches: CTDI(w, per), DLP, and isodose maps.

Purpose of the Study:

• To analyze and compare three shielding calculation methods for multislice CT installations.
• To determine the most reliable method for calculating radiation shielding barriers.

Main Methods:

• A comparative analysis of shielding calculation methods using measured and manufacturer-provided dosimetric data.
• Evaluation of barrier thicknesses for two different multislice CT scanners (Philips Brilliance 16 and 64).

Main Results:

• Shielding calculations based on isodose maps provide more reliable results than CTDI(w, per) or DLP methods.
• Isodose map calculations account for actual scattered radiation distribution, unlike other methods.
• Barrier thickness does not strictly increase with the number of slices; CT protocol techniques are significant.

Conclusions:

• The isodose map method is the most suitable for calculating CT facility shielding barriers.
• Effective shielding design depends on understanding scattered radiation patterns and CT protocol specifics.