Electron arc therapy: physical measurement and treatment planning techniques

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Post-mastectomy chest wall irradiation is crucial for reducing local recurrence.
• Conventional techniques may present challenges in achieving optimal dose distribution.
• Electron beam arc therapy offers a potential alternative for precise radiation delivery.

Purpose of the Study:

• To develop and evaluate an electron beam arc therapy technique for post-mastectomy chest wall treatment.
• To investigate the impact of various beam modifiers and energies on dose distribution.
• To optimize dose uniformity across the treated thoracic surface.

Main Methods:

• Utilized a clinical linear accelerator modified for arc therapy.
• Investigated effects of primary collimators, secondary (tray-mounted) and tertiary (cast) cerrobend blocks.
• Employed multiple electron energies (6-18 MeV), variable dose rates, and shaped applicators.
• Developed a computerized treatment planning program for visualization and optimization.
• Described a method to estimate secondary collimator width variation for thickness changes.

Main Results:

• Achieved optimized dose uniformity across the treated chest wall surface.
• Demonstrated the effectiveness of variable electron energies and shaped applicators.
• Presented a practical method for compensating for patient thickness variations.
• Provided a comparison of electron arc therapy dose distributions with standard techniques.

Conclusions:

• Electron beam arc therapy is a viable technique for post-mastectomy chest wall treatment.
• The developed method allows for precise dose optimization and uniformity.
• This technique holds promise for improving radiotherapy outcomes in breast cancer patients.