SU-E-T-441: A Feasibility Study to Replace Electron Cutouts with a Motorized Electron Multileaf Collimator.

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Fabricating electron beam cutouts is time-consuming and involves toxic cerrobend.
• Hospital workers face exposure risks to toxic fumes during cutout construction.
• There is a need for safer and more efficient methods for electron beam collimation.

Purpose of the Study:

• To assess the feasibility of replacing traditional electron cutouts with a prototype motorized electron multileaf collimator (eMLC).
• To evaluate the eMLC's effectiveness in clinical scenarios, particularly for electron boost treatments.

Main Methods:

• Compared treatment plans using eMLC-collimated beams versus applicator/cutout combinations for ten breast cancer cases.
• Utilized an in-house Monte Carlo-based treatment planning system for dose calculations on patient CT scans.
• Assessed treatment plan quality based on dose distribution and dose-volume histograms, investigating various leaf positioning strategies.

Main Results:

• Electron beams collimated by eMLC achieved comparable target coverage and critical structure sparing to traditional methods.
• The out-of-field leaf positioning strategy was identified as the most conservative and recommended approach.
• eMLC demonstrated effective dose distribution and sparing of critical structures.

Conclusions:

• The motorized electron multileaf collimator (eMLC) is a viable, time-saving, and pollution-free alternative to patient-specific cutouts.
• eMLC technology can significantly enhance safety and efficiency in radiation oncology.
• This technology eliminates the need for hazardous materials like cerrobend in electron beam therapy.