builds on the work jointly done by CERN and at the Lausanne University Hospital (CHUV) in a previous MA-funded project, which used the photon counting Timepix3 detector as a tool for radiation field characterisation. The goal of this new project is to use Timepix4 to innovate in all relevant areas of dosimetry instrumentation: accuracy, spectrometric capabilities, speed of data acquisition and transfer, reliability of dose measurement. There is an international need for better dosimetry devices, and the market is growing fast. However, there is not enough data available at this stage to predict the value of such market. CHUV is contributing with co-supervision of the doctoral student by the head of the Radioprotection and Medical Imaging of their Institute of Radiation Physics (IRA), as well as with the time of other IRA experts and access to interventional radiology and cardiology theatres and hybrid operating room for the measurements.