Medical Physics Seminar – Monday, October 25, 2010
Limitations of current dosimetry for intracavitary accelerated partial breast irradiation with high dose rate 192Ir and electronic brachytherapy sources
Julie Raffi (student of Dr. Larry DeWerd)
Research Assistant, Department of Medical Physics, UW-School of Medicine & Public Health, Madison, WI USA
Intracavitary accelerated partial breast irradiation (APBI) is a method of irradiating the breast after lumpectomy using a high dose rate (HDR) brachytherapy source positioned within the lumpectomy cavity. Dose distributions for these treatments are calculated using the American Association of Physicists in Medicine Task Group No. 43 (TG-43) formalism, which assumes a homogeneous water medium. This work is focused on investigating the limitations of TG-43 dose calculations for intracavitary APBI for two HDR sources, the VariSource™ VS2000 192Ir source and the Axxent® miniature x-ray source. TG-43 calculated doses are compared with TLD measurements and Monte Carlo calculations for phantom and patient geometries.