Fig. 1
From: Biology of high single doses of IORT: RBE, 5 R’s, and other biological aspects
Survival curves for irradiation of cells in vitro with 10 MeV electrons (20 mm water-equivalent depth) or 6 MV X-rays. The RBE of electrons was not significantly different from 1 (RBE = 0.98 ± 0.01; P = 0.10, n = 3) for MCF7 cells (a) while RBE was significantly reduced (RBE = 0.91 ± 0.02, P = 0.015, n = 3) after irradiation of HUVEC with higher doses (b). These experiments corroborated trends observed in independent experiments at lower doses (Additional file 2: Figures S1B, C)