Betatron electron beam characterisation for dosimetry calculations

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• Accurate dosimetry is crucial for effective radiation therapy.
• Existing models for electron beam dosimetry require refinement for clinical application.

Purpose of the Study:

• To establish parameters for electron beams (5-45 MeV) from a Brown Boveri betatron.
• To develop a semi-empirical equation for predicting dose distribution in water.
• To validate the accuracy of the model against established dosimetry requirements.

Main Methods:

• Modification of Kawachi's age-diffusion equation-based model.
• Development of a semi-empirical equation for dose calculation.
• Prediction of depth doses and isodose curves using practical range, SSD, and field size.

Main Results:

• Achieved depth dose accuracy of +/-2% above 50% dose and +/-5% below.
• Accurately predicted the shape of isodose curves, including constrictions and bulges.
• Demonstrated the utility of computer-calculated beams for summed isodose distributions.

Conclusions:

• The developed model provides accurate dosimetry predictions for clinical electron beam therapy.
• The parameters and equation are suitable for computerised dosimetry calculations.
• The findings support improved treatment planning in radiation oncology.