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Synchrotron stereotactic radiotherapy: dosimetry by Fricke gel and Monte Carlo simulations
Faculty of Engineering and Information Sciences - Papers: Part A
  • Caroline Boudou, European Synchrotron Radiation Facility
  • Marie-Claude Biston, European Synchrotron Radiation Facility
  • stéphanie corde, European Synchrotron Radiation Facility
  • Jean-Francois Adam, European Synchrotron Radiation Facility
  • Claudio Ferrero, European Synchrotron Radiation Facility
  • Francois Esteve, European Synchrotron Radiation Facility
  • Helene Elleaume, European Synchrotron Radiation Facility
Publication Date
Publication Details

Boudou, C., Biston, M., corde, s., Adam, J., Ferrero, C., Esteve, F. & Elleaume, H. (2004). Synchrotron stereotactic radiotherapy: dosimetry by Fricke gel and Monte Carlo simulations. Physics in Medicine and Biology, 49 (22), 5135-5144.

Synchrotron stereotactic radiotherapy (SSR) consists in loading the tumour with a high atomic number element (Z), and exposing it to monochromatic x-rays from a synchrotron source (50-100 keV), in stereotactic conditions. The dose distribution results from both the stereotactic monochromatic x-ray irradiation and the presence of the high Z element. The purpose of this preliminary study was to evaluate the two-dimensional dose distribution resulting solely from the irradiation geometry, using Monte Carlo simulations and a Fricke gel dosimeter. The verification of a Monte Carlo-based dosimetry was first assessed by depth dose measurements in a water tank. We thereafter used a Fricke dosimeter to compareMonteCarlo simulations with dosemeasurements. The Fricke dosimeter is a solution containing ferrous ions which are oxidized to ferric ions under ionizing radiation, proportionally to the absorbed dose. A cylindrical phantom filled with Fricke gel was irradiated in stereotactic conditions over several slices with a continuous beam (beam section = 0.1 × 1 cm2). The phantom and calibration vessels were then imaged by nuclear magnetic resonance. The measured doses were fairly consistent with those predicted by Monte Carlo simulations. However, the measured maximum absolute dose was 10% underestimated regarding calculation. The loss of information in the higher region of dose is explained by the diffusion of ferric ions. Monte Carlo simulation is the most accurate tool for dosimetry including complex geometries made of heterogeneous materials. Although the technique requires improvements, gel dosimetry remains an essential tool for the experimental verification of dose distribution in SSR with millimetre precision.
Citation Information
Caroline Boudou, Marie-Claude Biston, stéphanie corde, Jean-Francois Adam, et al.. "Synchrotron stereotactic radiotherapy: dosimetry by Fricke gel and Monte Carlo simulations" (2004)
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