A cytogenetic follow-up of some highly irradiated victims of the Chernobyl accident

Altres ajuts: The authors wish to thank INTAS (research grant no. 97-1152) for financial support for this workA follo w-up of 10 highly irradiated men, mostly reactor crew, from the Chernobyl accident is described. Their pre-accident medical conditions and relevant medical status approximately 10-13 y later are listed. A comparison is made between estimates of their average whole-body penetrating radiation doses derived from several biological parameters. First estimates were based on their presenting severity of prodromal sickness, early changes in blood cell counts and dicentric chromosome aberrations in lymphocytes. In three cases ESR measurements on tooth enamel were also made. Retrospective dosimetry using FISH translocations was attempted 10-13 y later. This showed good agreement for those patients with the lower earlier dose estimates, up to about 3 Gy. For the others, extending up to about 12 Gy, the translocations indicated lower values, suggesting that in these cases translocations had somewhat declined. Repeated chromosomal examinations during the follow-up period showed an expected decline in dicentric frequencies. The pattern of decline was bi-phasic with a more rapid first phase, with a half-life of ∼4 months followed by a slower decline with half-lives around 2-4 y. The rapid phase persisted for a longer time in those patients who had received the highest doses. 10-13 y later dicentric levels were still above normal background, but well below the translocation frequencies

The suitability of FISH chromosome painting and ESR-spectroscopy of tooth enamel assays for retrospective dose reconstruction

A comparative analysis of two groups of highly irradiated victims was carried out in order to evaluate the suitability of two assays for retrospective dose assessment: late translocations and electron spin resonance (ESR) dosimetry. The first group comprised 24 subjects who exhibited acute radiation syndrome (ARS) due to overexposure as a result of nuclear submarine accidents during the period 1961-1985. Their grades of ARS and individual doses were ascertained by Navy physicians who carried out primary examinations and treatment of the exposed seamen. Cytogenetic analyses were made 16-40 y after their accidents. During medical treatment seven tooth samples were collected for ESR analysis from this group. The second group consisted of ten highly irradiated men from the Chernobyl accident. Comparison was made between estimates of their average whole-body penetrating radiation doses derived from several biological parameters. In three cases ESR measurements on tooth enamel from this group were also made. Retrospective dosimetry using FISH translocations was attempted 10-13 y later. Yields of late translocations were in good agreement with initially estimated doses and with doses obtained by ESR spectroscopy analysis of tooth enamel long after exposure. It was concluded that both persisting stable translocations and ESR spectroscopy signals are suitable with similar efficiencies for retrospective biodosimetry after acute whole-body exposure