Medical Physics Seminar – Monday, March 7, 2011
Spectroscopic characterization of low-energy photon-emitting brachytherapy sources and kilovoltage x-ray beams
Jacqueline Moga (student of Dr. Larry DeWerd)
Research Assistant, Department of Medical Physics, UW-School of Medicine & Public Health, Madison, WI USA
Low-energy photons (20-300 keV) are used in radiotherapy primarily for brachytherapy and superficial therapy. Photons in this energy range present challenges for characterization due to their short range in medium and strong dependence on material composition. While current characterization techniques for low-energy photons typically utilize devices that integrate the measured signal, this work uses photon spectrometry to preserve the energy-specific information and investigate the dosimetry of these sources using the measured spectra. Germanium detectors were used for spectra measurements, and Monte Carlo simulations were used to account for detector response. Monte Carlo modeling of the sources was also used for comparison to the experimental results.