Print Email Facebook Twitter Time-resolved imaging of prompt-gamma rays for proton range verification using a knife-edge slit camera based on digital photon counters Title Time-resolved imaging of prompt-gamma rays for proton range verification using a knife-edge slit camera based on digital photon counters Author Cambraia Lopes, P. Clementel, E. Crespo, P. Henrotin, S. Huizenga, J. Janssens, G. Parodi, K. Prieels, D. Roellinghoff, F. Smeets, J. Stichelbaut, F. Schaart, D.R. Faculty Applied Sciences Department Radiation, Science and Technology Date 2015-07-27 Abstract Proton range monitoring may facilitate online adaptive proton therapy and improve treatment outcomes. Imaging of proton-induced prompt gamma (PG) rays using a knife-edge slit collimator is currently under investigation as a potential tool for real-time proton range monitoring. A major challenge in collimated PG imaging is the suppression of neutron-induced background counts. In this work, we present an initial performance test of two knife-edge slit camera prototypes based on arrays of digital photon counters (DPCs). PG profiles emitted from a PMMA target upon irradiation with a 160 MeV proton pencil beams (about 6.5 × 109 protons delivered in total) were measured using detector modules equipped with four DPC arrays coupled to BGO or LYSO : Ce crystal matrices. The knife-edge slit collimator and detector module were placed at 15 cm and 30 cm from the beam axis, respectively, in all cases. The use of LYSO : Ce enabled time-of-flight (TOF) rejection of background events, by synchronizing the DPC readout electronics with the 106 MHz radiofrequency signal of the cyclotron. The signal-to-background (S/B) ratio of 1.6 obtained with a 1.5 ns TOF window and a 3 MeV–7 MeV energy window was about 3 times higher than that obtained with the same detector module without TOF discrimination and 2 times higher than the S/B ratio obtained with the BGO module. Even 1 mm shifts of the Bragg peak position translated into clear and consistent shifts of the PG profile if TOF discrimination was applied, for a total number of protons as low as about 6.5 × 10.8 and a detector surface of 6.6 cm × 6.6 cm. Subject prompt gammaknife-edgetime-of-flightDPCproton therapy To reference this document use: http://resolver.tudelft.nl/uuid:dc28ad62-d175-4756-b5d0-fc99060581a3 Publisher IOP Publishing ISSN 0031-9155 Source Physics in Medicine and Biology, 60, 2015 Part of collection Institutional Repository Document type journal article Rights (c)2015The AuthorsPublished under the terms of the Creative Commons Attribution 3.0 licence Files PDF lopes2.pdf 3.67 MB Close viewer /islandora/object/uuid:dc28ad62-d175-4756-b5d0-fc99060581a3/datastream/OBJ/view