Low-dose radiation from CT examination induces DNA double-strand breaks and detectable changes of DNA methylation in peripheral blood cells

Figures & data

Figure 1. sample collection protocol.

Table 1. The minimum, maximum and average CTDL_vol, DLP and blood absorbed doses.

	minimum	median	maximum	average	SD
CTDIvol (mGy)	21.24	31.95	42.64	32.83	5.15
DLP (mGy·cm)	450.7	590.6	961.6	639.9	135.14
Blood absorbed Dose (mGy)	2.21	3.28	4.32	3.35	0.52

Abbreviations: CTDI_vol: CT dose index volume; DLP: dose length–product; FDR: false discovery rate.

Figure 2. Number of γ-H2AX foci per cell at different time points. (a) and (b) are Plots illustrating the number of foci per cell at three time points; (c) bar plot showing number of foci per cell at 1h and 24h minus number of foci per cell at 0h (participants with missing value were excluded in (a) and (C)).

Figure 3. Linear relationship between the increased number of γ-H2AX foci per cell and doses represented by (3a) CT dose index Volume (CTDIvol), (3d) dose length-product (DLP) and (3c) blood absorbed dose at 1h. Each blue dot represents a participant’s dose-focus counterpart, and the dotted lines are linear tend lines. The dotted line represents linear trends. R² is regression coefficient, y is linear regression expression.

Figure 4. Box plot of different leukocyte cells. Abbreviations: CD8 + T: CD8+ T lymphocytes; CD4 + T: CD4 + T lymphocytes; NK: natural killer cells.

Table 2. Comparisons of different leukocyte cells at three time points.

	0h(%)		1h(%)		24h(%)
Cell types	average	SD	mean	SD	mean	SD	p
B cells	5.9	1.5	6.4	1.5	6.3	1.3	.50
CD4^+T	10.7	3.7	10.5	3.2	11.2	2.8	.50
CD8^+T	15.7	3.4	15.1	2.8	16.4	3.4	.01
Monocytes	6.5	1.9	6.4	2.2	6.9	2.2	.33
Granulocytes	56.2	6.6	57.9	5.6	54.1	4.9	< .01
NK	5.7	2.1	4.4	2.2	5.4	2.3	.01

Abbreviations: CD8⁺T: CD8⁺ T lymphocytes; CD4⁺T: CD4⁺ T lymphocytes; NK: natural killer cells; SD: standard deviation. p values were calculated from paired t-test.

Figure 5. Beta-value of cg 14283649.

Table 3. FDR and the number of differentially methylated Positions with doses represented by different parameters.

	Compare Groups
Parameters	FDR	0h–1h	0h–24h	1h–24h
Time points	< 0.05	6	13	55
	< 0.1	35	47	227
CTDIvol(mGy)	< 0.05	2	12	–
	< 0.1	40	43	–
DLP(mGy·cm)	< 0.05	7	21	–
	< 0.1	84	54	–
Blood absorbed dose(mGy)	< 0.05	2	14	–
	< 0.1	16	57	–
Foci per cell (foci/cell)	< 0.05	190	1239	1360
	< 0.1	1563	5824	5166

Abbreviations: CTDI_vol: CT dose index volume; DLP: dose length–product; FDR: false discovery rate.