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Cancer risk due to low dose radiation has not been well
established. Estimates of this risk have been made using the high-dose data
from atomic bomb survivors at Hiroshima and Nagasaki under the assumption that
the risk is proportional to the radiation dose without a threshold. However,
we do not necessarily have the scientific evidence to support this assumption
of dose/effect linearity in the low-dose range.
Because it is difficult to assess the risk of low-dose
radiation from animal experiments or in epidemiological data, this group conducts
studies on the
mechanism of radiation effects caused by low-dose radiation.
The aim of the work is to derive findings useful in the
risk assessment of low dose radiation which can be used as a basis for the
development of appropriate
regulatory frameworks.
Major study items
- Evaluation of indirect effects of low-dose
radiation on carcinogenesis (carcinogenesis due to changes in the microenvironment
caused by irradiation) and examination of the involvement of DNA repair mechanisms
in low-dose radiation-induced carcinogenesis
- Clarification of low-dose radiation risk-modifying factors in nonhomologous
end-joining DNA-repair and its molecular mechanism
- Verification of the validity of radiation regulations relating to developmental
and differentiational anomaly by evaluating the effects of low-dose radiation
on abnormalities in neural crest cell differentiation
- Determination of risk modifying factors specific to low dose
radiation by identifying genes associated with biological responses to low-dose
radiation, including
radioadaptive responses and signal transduction