Evaluation of prototype of improved electron collimation system for Elekta linear accelerators

Area of Science:

• Medical Physics
• Radiotherapy Technology

Background:

• Elekta linear accelerators are widely used in radiotherapy.
• Electron beam applicators can be heavy, posing handling challenges for staff.
• Optimizing applicator design is crucial for improving clinical workflow and patient safety.

Purpose of the Study:

• To evaluate a novel electron collimation system for Elekta 6-20 MeV electron beams.
• To assess the potential for reducing applicator weights by 25%-30%.
• To ensure the new design meets critical performance standards for beam flatness and leakage dose.

Main Methods:

• Constructed prototype applicators (10x10 cm², 20x20 cm²) using lead for trimmer material and stepped outer-edge bevels.
• Utilized Monte Carlo (MC) modeling to simulate dose distributions for various applicator sizes and beam energies (7, 13, 20 MeV).
• Measured and calculated in-field flatness and out-of-field leakage dose at 1- and 2-cm water depths.

Main Results:

• Prototype applicator measurements correlated well with MC calculations for weight, flatness, and leakage.
• All simulated applicators and beam energies met strict in-field flatness tolerances (±3% major axes, ±4% diagonals).
• The design satisfied IEC specifications for out-of-field leakage dose.

Conclusions:

• The new electron collimation system design for Elekta 6-20 MeV beams is validated.
• The design offers significantly reduced applicator weights, enhancing usability for radiotherapy professionals.
• This system provides a foundation for a new generation of clinically viable, lighter electron applicators.