Medicine and Health Sciences Commons^™

Optimizing Respiratory Gated Intensity Modulated Radiation Therapy Planning And Delivery Of Early-Stage Non-Small Cell Lung Cancer, Ilma Xhaferllari

Electronic Thesis and Dissertation Repository

Stereotactic ablative body radiotherapy (SABR) is the standard of care for inoperable early-stage non-small cell lung cancer (NSCLC) patients. However, thoracic tumours are susceptible to respiratory motion and, if unaccounted for, can potentially lead to dosimetric uncertainties. Respiratory gating is one method that limits treatment delivery to portions of the respiratory cycle, but when combined with intensity-modulated radiotherapy (IMRT), requires rigorous verification. The goal of this thesis is to optimize respiratory gated IMRT treatment planning and develop image-guided strategies to verify the dose delivery for future early-stage NSCLC patients.

Retrospective treatment plans were generated for various IMRT delivery techniques, including …

The Impact Of Lateral Electron Disequilibrium On Stereotactic Body Radiation Therapy Of Lung Cancer, Brandon Disher

Electronic Thesis and Dissertation Repository

Stereotactic Body Radiation Therapy (SBRT) is an effective treatment option for patients with inoperable early-stage lung cancer. SBRT uses online image-guidance technology [e.g. cone-beam CT (CBCT)] to focus small-fields of high energy x-rays onto a tumour to deliver ablative levels of radiation dose (e.g. 54 Gy) in a few treatment fractions (e.g. 3). For the combination of these treatment parameters and a low density lung, lateral electron disequilibrium (LED) can potentially occur, reducing lung and tumour doses. The goal of this thesis was to determine the impact of LED on stereotactic body radiation therapy for lung cancer.

The effect of …

Strategies For Reducing The Impact Of Tumour Motion During Helical Tomotherapy, Bryan Kim

Electronic Thesis and Dissertation Repository

Tumour motion presents a significant limitation for effective radiotherapy of lung cancer, and more specifically for helical tomotherapy. The simultaneous and continuous movements of tomotherapy subsystems (gantry, couch, and binary multi-leaf collimator) can lead to inaccurate dose delivery, when combined with tumour motion. In this thesis, we have investigated the impact of tumour motion and strategies to reduce the resulting dose discrepancies for helical tomotherapy, through computer simulations and film measurements performed in a dynamic body phantom. Three distinctively different types of dose discrepancies have been isolated: dose rounding, dose rippling, and the intensity-modulated radiation therapy (IMRT) asynchronization effect. Each …