Access Type

Open Access Dissertation

Date of Award

January 2021

Degree Type


Degree Name



Medical Physics

First Advisor

Jacob Burmeister


Introduction: The treatment of cancer using intensity modulated radiation therapy (IMRT) is complex, involving many sub-processes to commission a treatment platform and treat patients. Uncertainties within the individual sub-process can lead to inaccurate treatments and sub-optimal patient outcomes. This research focused on minimizing uncertainties throughout IMRT commissioning and treatments. Methods: Five sub-processes were selected for uncertainty reduction: 1) optimizing radiation-imaging coincidence of the treatment machine, 2) improving the statistical model used to analyze IMRT commissioning data, 3) reducing the effect of ion recombination in IMRT quality assurance measurements, 4) improving the correlation between IMRT quality assurance results and patient-specific delivery inaccuracies, 5) commissioning of cranial stereotactic radiosurgery treatments. Results: Uncertainty reduction was achieved in all five sub-processes. Although the effect of this work on any single patient’s treatment is difficult to quantify, it is expected that the improvement in the sub-process accuracy will have a beneficial effect on the overall IMRT treatment delivery accuracy. Conclusion: Reducing uncertainties is an important aspect of radiotherapy quality assurance and should continue to be investigated for current and future treatment techniques.

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