Diamond Dosimeter for in Vivo Dosimetry for Synchrotron Radiotherapy

International audienceA significant proportion of cancer patients benefit from radiotherapy . Besides conventional x-ray radiation, synchrotron has proven to offer significant advantages in radiotherapy by using high dose rate coherent x-rays beams. Indeed, High coherence allowing to produce micrometric fields to explore limits of a concept called dose-volume effect. The other important characteristics of synchrotron radiation (high dose rate) permits to take advantage of the so-called flash effect.The first phase I/II clinical study of synchrotron radiotherapy at the European Synchrotron Radiation Facility (ESRF) demonstrated the feasibility and safety of this technique. this method requires some development. One of them, in-vivo dosimetry (the real time dose delivered during the treatment), is particularly challenging, because of the high dose rate and low energy flux.A new approach based on pixelised diamond detectors ,already validated for one point dosimetry in synchrotron radiation[1], will be developed.Before the full conception of one dimension dosimeter, first step is to characterize diamond detectors responses in synchrotron radiation (incident photons energy between 30 and 150 keV and an high dose rate which can reach 10 000 Gy/s) and show the project’s viability.For this reason, some preliminary tests was performed on different diamond detectors (two mono-crystalline and one polycrystalline), to show their response for different energy and dose rate, already developed at LPSC (Laboratoire de Physique Subatomique et Cosmologie) and this presentation will focus on these tests.[1]: Livingstone J. et al. Characterization of a synthetic single crystal diamond detector for dosimetry in spatially fractionated synchrotron x-rays fields. 201