Medical Physics Seminar – Monday, December 6, 2021
Development of standard x-ray beams for calibration of radiobiology cabinet and conformal irradiators
Emily King
Medical Physics Graduate Student
The American Association of Physicists in Medicine Task Group 61 (TG-61) has written a recommended protocol for determining dose to water in the energy range in which radiobiology x-ray irradiators operate. One assumption made in applying TG-61 to radiobiology irradiators is that the spectra in which dosimetry equipment is calibrated sufficiently matches the spectra of the radiobiology beams, even though these irradiators often operate at higher tube potentials and/or lighter filtration than available standard x-ray beams. The purpose of this project was to develop standard x-ray beams that are matched to common radiobiology irradiators: the PXi XRad320 and XStrahl SARRP which will aid in a more accurate dose determination during calibration of these irradiators.
Evaluation of the effects of filtration on the Xoft Axxent Source
Autumn Walter
Medical Physics Graduate Student
Low energy therapeutic photon sources have been shown to have a higher relative biological effectiveness, or RBE, when compared to megavoltage beam qualities. An example of one of these sources is the Xoft Axxent electronic brachytherapy source, which operates at tube potentials ranging from 40-50 kVp. Recently, a newer source model has been produced that uses a higher density, Galden coolant rather than the traditional water coolant. This change has both dosimetric and biological implications, which motivated this work to the newest Axxent source model for cervical cancer applications.