Reducing shield thickness and backscattered radiation using a multilayered shield for 6–10 MeV electron beams

Area of Science:

• Medical Physics
• Radiation Oncology
• Materials Science

Background:

• Electron shields in radiotherapy minimize radiation dose to healthy tissues during treatment.
• Electron backscatter radiation can increase dose on the beam side of shields.
• Current shield designs can be bulky, impacting patient setup and comfort.

Purpose of the Study:

• To design and evaluate a novel, thinner electron shield for radiotherapy.
• To minimize electron backscatter radiation and overall shield thickness.
• To improve clinical setup and patient tolerance during treatment.

Main Methods:

• A multi-material step-down filter shield incorporating lead, copper, aluminum, and wax was designed.
• The shield's performance was evaluated for electron beams ranging from 6 to 10 MeV.
• Backscatter and transmission reduction were measured and compared to a standard shield design.

Main Results:

• The new shield design (7.1 mm total thickness) achieved comparable backscatter and transmission reduction to a standard 14.5 mm shield.
• Dose enhancement was limited to no more than 10% with the novel shield.
• A 50% reduction in shield thickness was achieved.

Conclusions:

• The developed electron shield effectively minimizes backscatter radiation while significantly reducing overall thickness.
• The thinner shield design facilitates easier patient setup and improves patient comfort, particularly during mucosal reactions.
• This optimized shield represents a practical advancement in radiotherapy shielding technology.