Semester Award Granted

Spring 2025

Submission Date

May 2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Thesis/Dissertation Advisor [Chair]

Andreas Kyriacou

Abstract

This work examines the Elekta Monaco TPS Monte Carlo electron beam dose calculation model for electron treatment planning. The primary goals are to commission electron blocks and establish correction factors for diode measurements with the use of ion chamber output as references, improving dosimetric procedures and adhering to the AAPM for clinically acceptable precision. Output factor measurements of diodes were compared to ion chamber OFs on a 6 MeV to 15 MeV Elekta Versa HD linear accelerator. TPS calculations were held on the Monaco TPS system. To balance the computational costs and accuracy of the solution, grid sizes of 2 mm x 2 mm and 3 mm x 3 mm were selected and histories of 100,000 and 200,000 were studied. It was found that a 3 mm grid size carrying 100,000 histories was used as the standard to maintain the deviations between the measured and calculated values at 3%.

Calibration of diode-based dose verification against the ion chamber and TPS data was done and the system has linear correlation and thus minimizing ion chamber measurements in routine clinical applications. The results confirm TPS model to allow static electron field calculation and optimization with a treatment planning accuracy within a 5% tolerance level. This improves workflow while not affecting clinical accuracy in anyway.

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