Study and development of a new real time dosimetric system, dedicated to IORT (Intra Operative Radiation System)

IntraOperative Radiation Therapy (IORT) is a technique based on delivery of a high dose of ionising radiation to the cancer tissue, after tumour ablation, during surgery, while reducing the exposure of normal surrounding tissue. The Novac7 is a new linear accelerator expressly conceived to perform in the operating room. This accelerator supplies electron beams at several energy, with high dose rate. These peculiar characteristics give rise to some complications with classical dosimetric techniques. In the framework of a research contract between ENEA and the Physics Department of Bologna, an original system has been developed to study and visualise the Novac7 electron beam in real time. The system is composed by an electron-light converter, a mirror to focalise the light on a CCD sensor and a computer with dedicated software to acquisition, visualisation and imaging. On the prototype theoretical and experimental studies have been conducted. It was verified that the system is able to get linear and stable responses on changing impulse number and energy. Moreover the experimental results have been compared with the ones obtained from classical instruments. The results are totally satisfactory: the system is able to get a real time representation of the electron beam and the developed software can give several interesting additional information on beam.