Fig. 3

Particle irradiation leads to heterogeneous increases in apoptosis induction of esophageal cancer cells. Percentage of apoptotic EC cells accessed by the sub-G1 fraction and cellular caspase-3 activation measured at 96 h after irradiation with biologically isoeffective doses of photons (X), protons (¹H) and heavy ions (¹²C, ¹⁶O) (mean and SD of n = 3 replicate samples). *p < 0.05, **p < 0.01 (two-sided Student’s t-test against unirradiated controls)