This paper concerns the development of a novel monolithic active pixel radiation sensor based on SOI technology. In this device, the sensitive volume corresponds to a high resistivity SOI "handle" wafer and the front-end CMOS electronics is integrated in the SOI device layer. Pixel test matrices have been manufactured and are under extensive characterization. The conceptual design, together with architecture and technology issues is addressed; the latest experimental results are reported.

Real time dosimetry is a critical issue in most radiotherapy applications. SUCIMA (Silicon Ultra fast Cameras for electron and gamma sources In Medical Applications) is a project addressing the development of an imaging technique of extended radioactive sources based on monolithic and hybrid position sensitive silicon sensors, where "imaging" has to be understood as the record of a dose map. The requirements for the detectors are given by the main applications, namely brachytherapy and real time monitoring of a proton beam for oncology. The key issues in the sensor and DAQ development are described together with the most relevant medical applications. SUCIMA is a project supported by the European Commission.