Dosimetric study of therapeutic beams using a homogeneous scintillating fiber layer

Currently, radiotherapy with electrons and photons beam is the most common approach in health care facilities; it allows a wide diffusion of the technology. Only a fast and accurate verification of the dose characteristics of the beams provides a safe and effective use of the methodology. However, the tool most commonly used for dose quality controls is the ionization chamber with the water phantom, which takes long time for the required measures. The research for new tools has increased in recent years to provide the required information more quickly. We have designed, built and tested a new tool based on a layer of square scintillating fibers of thickness 0.5 mm that can run a scan of the beam. The system provides both the dose profiles, related to a plane orthogonal to the beam axis at fixed depth, and the dose delivered in depth. The device was tested with a beam of 6MV photons. The beam was delivered by a linear accelerator Varian Clinac DHX 2100. The data collected were processed for the tomographic reconstruction of the dose by means of the FBP (filtered back projection) algorithm with different filters. An iterative reconstruction algorithm was also tested. In this paper, the results are presented and suggestions for future developments are described.