Radiation signature on exposed cells: Relevance in dose estimation

Table 1 World wide annual per capita effective doses in year 2000 (UNESCAR 2000)

Source	Worldwide annual per capita effective dose (mSv)
Natural background	2.4
Diagnostic and medical examinations	0.4
Atmospheric testing	0.005
Chernobyl	0.002
Nuclear power production	0.0002

Table 2 A few characteristic features of established bio-markers

S. No	Parameter	Technique
		DC	MN	FISH	γ-H2AX
1	Culture time (h)	48	72	48	Not applicable
2	Scoring speed (cells/d)	About 150	About 750	About 750	About 100/h
3	Type of aberrations detectable	Unstable	Unstable	Stable/ unstable	Unstable
4	Period of detection after exposure (yr)	2-3	2-3	> 30	2-3 d
5	Cell type/quality	Metaphases/ good	BN cells/good	Metaphases/good	Interphase cells/good
6	Baseline frequency	0.001	0.015	0.001	0.042
7	Sensitivity (Gy)	0.1	0.25	0.1	0.05

FISH: Fluorescence in situ hybridization; MN: Micronucleus; DC: Dicentric chromosome.