BIODOSIMETRY USING CHROMOSOMAL TRANSLOCATIONS MEASURED BY FISH IN A POPULATION CHRONICALLY EXPOSED TO LOW DOSE-RATE CO-60 GAMMA- IRRADIATION
Resource
INTERNATIONAL JOURNAL OF RADIATION BIOLOGY v.77 n.7 pp.797-804
Journal
INTERNATIONAL JOURNAL OF RADIATION BIOLOGY
Journal Volume
v.77
Journal Issue
n.7
Pages
797-804
Date Issued
2001
Date
2001
Author(s)
CHAN, CHANG-CHUAN
Abstract
Purpose: To evaluate the cumulative gamma -radiation
personal exposure by analysing lymphocyte chromosome
translocations using FISH painting and to compare FISH-
derived biodoses with those derived from retrospective
physical dose reconstruction in residents receiving chronic
low dose-rate gamma -irradiation while living in radio-
contaminated buildings. Materials and methods: Chromosome
translocation frequencies were evaluated by scoring 933 3077
metaphases under fluorescence microscope for each of the
five male and four female exposed individuals after they had
relocated from the radioactive environment for 34 and 82
months. FISH painting was conducted using kits of whole-
chromosome probes for chromosomes 1, 2 and 4 in orange and 3
, 5 and 6 in green and counter-stained with 4',6-diamidino-2
-phenylindole (DAPI). The retrospective dose estimation
termed Taiwan Cumulative Dose (TCD) was conducted by
assessment using detailed information of historical exposure
and the environmental radioactivity for each apartment
during previous residency. Results: A total of 20 244 well-
prepared metaphases were scored. Biodoses were calculated
from the translocation frequencies and physical doses were
estimated from detail questionnaires for each individual.
The translocation frequencies measured ranged from 2.2 x 10(
-3) to 26.8 x 10(-)3 translocations per cell and the dose
equivalent from 52.2 to 992.2 mSv. A good correlation was
observed between the physical and biodoses. A plot of TCD
against FISH-derived doses produced D-fish = 0.65 D-rCD,
when fitted by a linear model, and D-fish = 0.53 D-rCD + 1.
26 x 10(-4) D-TCD(2), when fitted with a linear quadratic
model. Given the scatter in the data and the extremely small
quadratic dose contribution, neither model could be ruled
out. Conclusion: Chromosome translocations provide a valid
method of dose estimation in extremely protracted low dose-
rate gamma -radiation exposure. Validation of the TCD method
by FISH-measured translocations supports the use of TCD for
epidemiological studies.
Subjects
IN-SITU HYBRIDIZATION
IONIZING-RADIATION
BIOLOGICAL DOSIMETRY
SYMMETRICAL TRANSLOCATIONS
CLEANUP WORKERS
LYMPHOCYTES
Type
journal article