Equivalent uniform dose for accelerated partial breast irradiation using the MammoSite applicator.

Abstract

INTRODUCTION This study aims to quantify the radiobiology of the MammoSite applicator and examine whether there is a relationship between equivalent uniform dose (EUD) and radiotherapy-associated toxicity. METHODS AND MATERIALS A previously-published version of the linear quadratic (LQ) model, designed to address the impact of dose-gradients in brachytherapy applications, was used to determine the biological effective dose (BED), equivalent dose in 2 Gray per fraction (EQD2) and EUD for the most common fractionation scheme for the MammoSite catheter (34 Gy in 10 fractions prescribed to 1cm from the balloon surface), using a range of balloon sizes in a series of patients treated with single or multiple dwell positions. Toxicity from the MammoSite catheter was assessed and statistical associations with the calculated EUDs were investigated. RESULTS The acute- and late-toxicity EUDs respectively range from 34.8-39.4 Gy and 33.4-37.6 Gy, with EUD decreasing as balloon diameter increases and/or the number of dwell positions increases. There was a positive association between EUD and hyperpigmentation and telangiectasia. CONCLUSIONS For APBI using the Mammosite applicator, EUD is higher than the marginal prescription dose and, for the dose-fractionation patterns considered here, was associated with acute and late skin toxicity. EUD is a potentially useful parameter to characterize non-uniform dose distributions related to brachytherapy treatments. Further evaluation in future studies is warranted.

DOI: 10.1016/j.radonc.2013.06.030

Cite this paper

@article{Stewart2013EquivalentUD, title={Equivalent uniform dose for accelerated partial breast irradiation using the MammoSite applicator.}, author={A. James Stewart and Jaroslaw T. Hepel and Desmond A. O'Farrell and Phillip M. Devlin and Lori Lyn Price and Roger G Dale and David E. Wazer}, journal={Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology}, year={2013}, volume={108 2}, pages={232-5} }