AUTHOR=Llosá Gabriela, Trovato Marco, Barrio John, Etxebeste Ane, Muñoz Enrique, Lacasta Carlos, Oliver Josep F., Rafecas Magdalena, Solaz Carles, Solevi Paola TITLE=First Images of a Three-Layer Compton Telescope Prototype for Treatment Monitoring in Hadron Therapy JOURNAL=Frontiers in Oncology VOLUME=6 YEAR=2016 URL=https://www.frontiersin.org/articles/10.3389/fonc.2016.00014 DOI=10.3389/fonc.2016.00014 ISSN=2234-943X ABSTRACT=A Compton telescope for dose monitoring in hadron therapy is under development at IFIC. The system consists of three layers of LaBr3 crystals coupled to silicon photomultiplier arrays. 22Na sources have been successfully imaged reconstructing the data with an ML-EM code. Calibration and temperature stabilization are necessary for the prototype operation at low coincidence rates. A spatial resolution of 7.8 mm FWHM has been obtained in the first imaging tests.