Dose assessment by quantification of chromosome aberrations and micronuclei in peripheral blood lymphocytes from patients exposed to gamma radiation

Isvânia Silva-Barbosa,Símey Pereira-Magnata,Graça Sotero,Homero Cavalcanti Melo,Ademir Amaral

doi:10.1590/s1415-47572005000300021

Abstract

Scoring of unstable chromosome aberrations (dicentrics, rings and fragments) and micronuclei in circulating lymphocytes are the most extensively studied biological means for estimating individual exposure to ionizing radiation (IR), which can be used as complementary methods to physical dosimetry or when the latter cannot be performed. In this work, the quantification of the frequencies of chromosome aberrations and micronuclei were carried out based on cytogenetic analyses of peripheral blood samples from 5 patients with cervical uterine cancer following radiotherapy in order to evaluate the absorbed dose as a result of partial-body exposure to 60Co source. Blood samples were collected from each patient in three phases of the treatment: before irradiation, 24 h after receiving 0.08 Gy and 1.8 Gy, respectively. The results presented in this report emphasize biological dosimetry, employing the quantification of chromosome aberrations and micronuclei in lymphocytes from peripheral blood, as an important methodology of dose assessment for either whole or partial-body exposure to IR.

Highlights

Absorbed dose is the most important physical quantity for evaluating potential biological response as a result of exposure to ionizing radiation (IR)
Physical dosimetry is commonly performed by instruments that are sensitive to the physical effects of IR
Biological dosimetry is based on the investigation of radioinduced biological effects in order to correlate them with the radiation dose

Summary

Introduction

Absorbed dose is the most important physical quantity for evaluating potential biological response as a result of exposure to ionizing radiation (IR). In most cases involving real or suspected accidental exposure, people are not wearing a dosimeter and, as a result, physical dosimetry is not straightforward. For such situations, the study of early biological effects induced by an exposure to IR has been proposed as either a complementary or an alternative method for dose assessment (Downing, 2000; Amaral, 2002; Bonassi and Au, 2002; Ramalho and Nascimento, 1991; Ramalho et al, 1995; Voisin et al, 2001). Unstable CA (dicentrics, rings and fragments) are generally considered as specific to radiation exposure, and these types of aberrations are referred to as unstable CA because of their persistence in the body decline with cell division cycles (Amaral, 2002)

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Conclusion