By calculating the spectra peaks of corresponding metabolites, the relative concentration of metabolites was acquired. Single-variable analysis was performed to validate the statistical difference. For each metabolite, 1 or 2 non-overlapping or little-overlapping spectrum peaks were selected as specific spectrum peaks to calculate the integral area by which the relative concentration of each metabolite was acquired (Table 1). The relative concentration of differentially expressed metabolites was performed in a non-parametric statistical test of single variable to generate a p value by the Mann–Whitney test, and the differentially expressed metabolites with statistical significance were indicated in Fig 3 (* p < 0.05, ** p < 0.01). Consistent with the results of multivariable analysis, in response to radiation, the contents of alanine, glutamate, choline and glycine were increased, while the content of leucine, lactate, acetate, creatine, creatine phosphate, methanol, UDP-glucose, and ATP were decreased.