Fully-organic indirect flexible detector for real-time dose monitoring during proton therapy

The development of detectors for protons and heavy particles is a long-lasting research topic not only for fundamental applications but also, more recently, for monitoring energy and flow of particles in ion beam applications. Nowadays, one of the most demanding application of ion beams is hadron therapy of cancer. In this field, ion beams, mostly proton beams, are used for the controlled treatment of cancer by focusing them onto small volumes to deliver energy to the tumor. The effectiveness and safety of the treatment is enhanced by tuning the beam both in intensity and in position to irradiate the tumor in a controlled way, preserving the surrounding healthy tissues. For this reason, there is an increasing demand of systems optimized for the accurate recording and mapping of the dose delivered during a treatment plan in-situ and in realtime. Here, we present the results achieved by a fully-organic indirect detector in which a flexible Organic Photo-Transistor based on DNTT has been coupled with a plastic scintillator based on polysiloxane. The device has been firstly characterized under 5 MeV proton beams provided by LABEC ion beam center (INFN - FI, Italy) to reproduce the energy range that scattered protons deliver on healthy tissues surrounding the tumor during treatments for prostate cancer. The detector exhibits excellent detecting performances even bent down to a curvature radius of 0.5 mm, at low operation voltages (V = -1 V), reaching a limit of detection of 0.0 6 Gy min -1 . Such results confirm its reliability as a personal dosimeter with high comfort and low risk for the user. Finally we tested the detectors in real clinical conditions employing an anthropomorphic phantom and a therapeutic proton beam (energy range [70–00] MeV) provided by TIFPA Proton Therapy Center (TN, Italy).