Diamond detector based microdosimetry: key solution in the determination of the radiobiological effectiveness?

Abstract

Hadron therapy offers a higher dose conformity and potential increase of radiobiological effectiveness (RBE), compared to conventional radiation therapy. The arrival of proton therapy in Belgium emphasises the importance of developing a way that could not only accurately represent the dose delivered to the patient, but that could also address the problem of RBE in clinical conditions. We think that microdosimetry, the measurement of stochastic energy deposition distributions in a micrometre size sensitive volume, could provide an efficient tool for assessing these differences in radiation quality. Although tissue-equivalent proportional counters remain the gold standard for experimental microdosimetry, diamond has promising properties to be operated as radiation detector, due to its radiation hardness, chemical stability and absolute nontoxicity. Furthermore, diamond is tissue equivalent. This research aims to investigate the possibilities of a prototype high-purity single crystal diamond detector as microdosimeter. Based on the lab experiments, it is concluded that this diamond microdosimeter has excellent capabilities: a resolution of 10 keV/μm and a lower detection limit of 10 keV/μm are obtained.