Patient specific quality assurance (PSQA) is an essential part of the radiotherapy workflow for both particles and photons, aiming to validate the agreement between the planned and real dose distribution. This validation can be performed either by an empirical measurement of each individual treatment plan or by a recalculation of the relevant dose distribution with an independent software. Both approaches are currently well-established for a treatment in recumbent position. The adaptation to a treatment delivery in upright position is needed. Moreover, as the treatment and therefore positioning of the patient upright is a paradigm shift with very limited experience and with lack of clinical data on positioning accuracy, the PSQA program must be able to verify the positioning precision in all directions including a chair rotation.  

The aim of the project is to develop a PSQA procedure for a verification of safe treatment plan delivery for a patient in upright position during photon and particle radiotherapy. Two strategies will be developed: one for both imaging for treatment planning and treatment delivery itself performed in upright position; second one for treatment planning imaging performed recumbent and treatment delivery upright. The developed PSQA will validate the accuracy of the coordinate transfer and dose delivery. The first essential step will be a systematic analysis of what needs to be validated and how, followed by a concept proposal and a definition of guidelines for PSQA based on measurements and independent dose calculation. Afterwards, a novel QA phantom will be designed enabling simultaneous evaluation of dosimetric and positioning accuracy. A potential outline of such a device is a chair-mounted rotational phantom with an integrated commercial detector, controlled by a user interface that will move the phantom and analyse the acquired data. The last step will consist of an adaptation of an open-source software for an independent dose calculation to enable recalculation of the treatment plans planned on the upright 3D imaging. 

The work will be done in close collaboration with DC8 focusing on software developments.