In radiotherapy, patients are typically treated in supine position, with the arm of the linear accelerator rotating around the patients. The preparatory CT-scan (i.e. the planning CT) is thus performed in the same position as typically done for diagnostic imaging. 

However, several recent studies suggested that patient positioning in an upright position (sitting or standing) could improve treatment delivery to some tumor locations. In pelvic tumors, in upright positioning, the bladder is more elongated in anterior posterior direction and the distance between the sacrum and the bladder is reduced, suggesting that the small bowel could be spared more efficiently during radiotherapy. In the thorax, it has been shown that the breathing motion and especially the cranio-caudal movement is significantly reduced, thus contributing to the generation of a much smaller PTV, thus allowing irradiation of less lung tissue. In head and neck tumor, on top of improved patient comfort, upright positioning could better separate the tumor volume from the posterior pharyngeal wall, thus contributing to lower dose delivery on the constrictor muscles, thus less radiation-induced dysphagia. 

In this framework, the goal of the project is to demonstrate and quantitate the advantages and disadvantages of up-right radiotherapy patient positioning in comparison to the standard positioning for head and neck, lung and breast cancer patients. More specifically this project will focus on patient positioning set-up for patients with lung, breast and head and neck tumors. 

Tasks: 

• To define the optimal up-right patient setting in term of seat position, back rest angle, arm positioning, need of bra (for breast tumor) and back vacuum cushion for patients with lung and breast cancer. 

• To quantitate the positioning accuracy using a surface guiding system and assess the intra-fraction and inter-fraction variability for patients with lung and breast cancer. 

• To assess the patient satisfaction when position in comparison with the supine positioning using a Lykert scale. for patients with lung and breast cancer 

• To define the protocol for the up-right CT-scan acquisition for patients with lung and breast cancer. 

• To contribute in collaboration with a radiation oncologist to the delineation of the organs-at-risk for patients imaged in up-right positioning for patients with lung and breast cancer.  
• To contribute in collaboration with a radiation oncologist to the definition of the optimal clinical workflow for patients treated in up-right position.