Animal studies and cancer BAF312 therapy investigations data showed that the cfDNA concentration increases along with the radiation dose rise within a wide high dose range , , ,  and . Fig. 1С shows the cfDNA concentration dependences on the total radiation dose. Still the linear regression method did not reveal the cfDNA concentration dependence on the total radiation dose in any of the three groups (С: k = −0.02, p = 0.80, N = 109; for GN: k = −0.01, p = 0.90, N = 88; and for T: k = −0.04, p = 0.70, N = 88). In the control group, the total radiation doses from medical diagnostic procedures for 109 individuals varied from 0.01 up to 4.34 REM. For one person only of 64 years the dose was 10.12 REM. The GN- and T-groups were divided into two sub-groups: (1) people with the total dose approximately similar to the doses in the control group (less than 4.34 REM), and (2) people with the total dose exceeding 4.34 REM. It turned out that the cfDNA concentration in the sub-groups of the exposed people from the GN- and T-groups, who had got the radiation dose higher than 4.32 REM, did not differ statistically from the cfDNA concentration in the sub-groups of the individuals, who had obtained the total radiation dose comparable with that received by some individuals from the control group during diagnostic procedures (for GN: D = 0.24, α = 0.14, n1 = 38, n2 = 50; for T: D = −0.17, α = 0.58, n1 = 50, n2 = 38). With respect to the control group, no difference was found in the cfDNA concentration between people, who had or had not been exposed during medical procedures (D = 0.09, α = 0.72, n1 = 45, n2 = 64). Thus, the cfDNA concentration virtually does not depend on the total IR absorbed dose within the considered dose range of the chronic exposure to the ionizing radiation.