Four-dimensional imaging in radiotherapy for lung cancer patients

Lung cancer is the most common cause of cancer related death. Overall survival is often poor after treatment with conventional radiotherapy. Improvements may be obtained by increasing the radiation dose; however, this can lead to unacceptable complications of healthy organs in or near the irradiation field. The size of the irradiation field is defined by the size of the tumor plus a treatment margin, to allow for geometrical uncertainties during treatment. The aim of this thesis is to reduce respiration-related geometrical uncertainties by improved imaging, creating patient-specific treatment plans. As a result treatment dose can be increased and/or the risk of complications reduced. For this purpose, four-dimensional imaging acquisition and post-processing techniques were developed and implemented in the clinic.