Both for external and internal exposure, chromosome aberrations
and/or micronuclei in lymphocytes
seem to be the most sensitive for the follow-up of workers exposed to ionizing radiation.
For further information see the CRIOS website:
http://cdfc00.rug.ac.be/HealthRisk/ionizing_radiation/ionizing_radiation.htm
References:
Touil N., Elhajouji A., Thierens H., Kirsch-Volders
M. "Analysis of chromosome loss and chromosome segregation in
cytokinesis-blocked human lymphocytes: non-disjunction is the prevalent mistake
in chromosome segregation produced by low dose exposure to ionizing
radiation", Mutagenesis, 2000, 15(1): 1-7.
Touil N., Aka P.V., Buchet J.P., Thierens H., Kirsch-Volders M.
"Assessment of genotoxic effects related to chronic low level exposure to
ionizing radiation using biomarkers for DNA damage and repair", Mutagenesis,
2002, 17(3): 223-232.