Phd defense by Jenny Elisabeth Gorgisyan – Niels Bohr Institute - University of Copenhagen

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Niels Bohr Institute > Calendar > NBI Calendar 2017 > Phd defense by Jenny E...

Phd defense by Jenny Elisabeth Gorgisyan

Evaluation of the breath-hold approach in proton therapy of lung tumors

Proton therapy has the potential to improve the treatment effect as compared to conventional radiation therapy for lung cancer patients. However, the proton therapy delivery is prone to uncertainties caused by anatomical changes and motion during the treatment and between the treatment fractions which may compromise its effectiveness. Breath-hold has been suggested as a motion management technique to mitigate the effect of this motion. The aim of this thesis was to investigate the robustness of the breath-hold approach for pencil beam scanned (PBS) proton therapy. More specifically, the residual motion as seen on repeated breath-hold computed tomography (CT) scans and fluoroscopy acquisitions were investigated using simulation and experimental studies. The results show that the PBS proton therapy treatment plans are in a majority of the cases robust to the residual breath-hold motion. The change in water-equivalent path length (WEPL) is further shown to be a good predictor of plan robustness, in addition to baseline shifts of the tumor. Overall, the results of this thesis encourage a clinical implementation of the breath-hold approach.

Supervisor
Per Munch af Rosenschöld

Assessment committee
Chair: Thomas Døssing
Opponent: Marco Schwarz, Proton Therapy Center, Trento, Italy
Opponent: Per Rugaard Poulsen, Rigshospitalet