Delivery of modulated electron beams with conventional photon multi-leaf collimators

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Electron beam radiotherapy is established for superficial tumors.
• Customizing electron dose distributions has been challenging.
• Existing modulation techniques have limitations.

Purpose of the Study:

• To investigate the feasibility of using photon multi-leaf collimators (MLC) for modulated electron radiotherapy (MERT).
• To develop and validate a method for customized electron dose distributions using MLC.
• To assess the clinical applicability of MERT for shallow tumor treatment.

Main Methods:

• Monte Carlo calculations for treatment planning, as commercial systems lack MLC support for electrons.
• Configuration, calculation, and delivery of segmented and dynamic modulated electron beams.
• Validation using phantoms and comparison with measurements.
• Application to clinical treatment plans for post-mastectomy and scalp cutaneous lymphoma.

Main Results:

• Successful validation of MERT using photon MLC with calculations and measurements agreeing within +/-2%/2 mm.
• Demonstrated efficient and safe delivery of modulated electron beams.
• Achieved optimal dose coverage for target volumes while sparing organs at risk in clinical plans.

Conclusions:

• Modulated electron radiotherapy (MERT) is feasible using photon MLC.
• The dynamic delivery of MERT is efficient and safe, making it ideal for shallow tumor treatment.
• This approach offers a promising method for customized electron radiotherapy.