Internal lead shielding for clinical electron treatments

Area of Science:

• Medical Physics
• Radiation Oncology
• Biomedical Engineering

Background:

• Electron beams are crucial for treating superficial lesions on the face.
• Lead shielding is used to protect healthy tissues, requiring an internal bolus to mitigate backscatter.
• Limited space necessitates precise calculations for lead and bolus thickness.

Purpose of the Study:

• To develop a new, self-consistent method for estimating lead and internal bolus thickness.
• To optimize thickness for electron beam energies (4-10 MeV) and varying tissue depths.
• To limit dose enhancement at the tissue/bolus interface to 10%.

Main Methods:

• A novel calculation method was devised for determining minimum lead and internal bolus thickness.
• The method accounts for incident electron beam energies and overlying tissue thickness.
• Gafchromic film measurements were used for validation.

Main Results:

• The new method provides a quick, accurate, and self-consistent estimation.
• It determines the minimum necessary thickness for both lead and internal bolus.
• Validation confirmed the method's accuracy and its ability to limit dose enhancement.

Conclusions:

• The developed method offers an improved approach to bolus and lead shielding in electron beam therapy.
• It ensures optimal radiation delivery to superficial lesions while protecting underlying structures.
• This technique enhances the safety and efficacy of superficial radiation treatments.