Biological Dosimetry in a Group of Radiologists by the Analysis of Dicentrics and Translocations

Page 1

RADIATION RESEARCH

164, 612–617 (2005)

0033-7587/05 $15.00 q 2005 by Radiation Research Society. All rights of reproduction in any form reserved.

Biological Dosimetry in a Group of Radiologists by the Analysis of Dicentrics and Translocations A. Montoro,a P. Rodrı´guez,b M. Almonacid,a J. I. Villaescusa,a G. Verdu´,c M. R. Caballı´n,d L. Barriosb and J. F. Barquinerod,1 a Servicio de Proteccio´n Radiolo´gica, Hospital Universitario La Fe, E-46009, Valencia, Spain; b Unitat de Biologia Cel·lular, Dpt. Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Cie`ncies, Universitat Auto`noma de Barcelona, E-08193, Bellaterra, Spain; c Dpt. Enginyeria Quı´mica i Nuclear, Escola Superior d’Enginyers Industrials, Universitat Polite`cnica de Valencia, E-46022, Valencia, Spain; and d Unitat d’Antropologia, Dpt. Biologia Animal, Biologia Vegetal i Ecologia, Facultat de Cie`ncies, Universitat Auto`noma de Barcelona, E-08193, Bellaterra, Spain

phases has provided the most reliable biological dosimetry, and it has been used widely for this purpose. This method has been used not only to assess acute doses but also to evaluate protracted doses like those received occupationally. Analysis of dicentrics is considered to be an important component of investigations of radiological exposures (1). However, because dicentrics are unstable aberrations, cells carrying dicentrics are eliminated from the peripheral blood lymphocyte pool, and the dose estimated by dicentrics will therefore tend to decrease with time postirradiation (2, 3). For past or chronic exposures, an alternative to the conventional use of dicentrics is the analysis of translocations. After an exposure to ionizing radiation, translocations are induced at a frequency similar to that of dicentrics (4), but translocations are stable aberrations whose yield remains relatively constant over time (5, 6). Translocations can be detected easily by fluorescence in situ hybridization (FISH), and their analysis is a valuable tool in cases of old or longterm exposures (7, 8). The present study was performed because lesions in the first three fingers from both arms, compatible with radiodermatitis, were detected in an interventional radiologist during the yearly medical examination of workers occupationally exposed to ionizing radiation. Due to the elevated yield of dicentrics detected in this radiologist (threefold higher than the background level), and to the anxiety in the rest of the group, a study analyzing dicentrics and translocations was carried out in nine individuals.

Montoro, A., Rodrı´guez, P., Almonacid, M., Villaescusa, J. I., Verdu´, G., Caballı´n, M. R., Barrios, L. and Barquinero, J. F. Biological Dosimetry in a Group of Radiologists by the Analysis of Dicentrics and Translocations. Radiat. Res. 164, 612–617 (2005). The results of a cytogenetic study carried out in a group of nine radiologists are presented. Chromosome aberrations were detected by fluorescence plus Giemsa staining and fluorescence in situ hybridization. Dose estimates were obtained by extrapolating the yield of dicentrics and translocations to their respective dose–effect curves. In seven individuals, the 95% confidence limits of the doses estimated by dicentrics did not include 0 Gy. The 99 dicentrics observed in 17,626 cells gave a collective estimated dose of 115 mGy (95% confidence limits 73–171). For translocations, five individuals had estimated doses that were clearly higher than the total accumulated recorded dose. The 82 total apparently simple translocations observed in 9722 cells gave a collective estimated dose of 275 mGy (132–496). The mean genomic frequencies (3100 6 SE) of complete and total apparently simple translocations observed in the group of radiologists (1.91 6 0.30 and 2.67 6 0.34, respectively) were significantly higher than those observed in a matched control group (0.53 6 0.10 and 0.87 6 0.13, P , 0.01 in both cases) and in another occupationally exposed matched group (0.79 6 0.12 and 1.14 60.14, P , 0.03 and P , 0.01, respectively). The discrepancies observed between the physically recorded doses and the biologically estimated doses indicate that the radiologists did not always wear their dosimeters or that the dosimeters were not always in the radiation field. q 2005 by Radiation Research Society

MATERIAL AND METHODS INTRODUCTION

Blood Sampling and Culture

Since the early 1960s, cytogenetic dose estimation based on analysis of dicentric chromosomes in solid stained meta-

The study was approved by the Specialized Medical Safety Section of the Hospital la Fe in Valencia. Blood samples were obtained according to the general principles on health and safety at work in Spain, described in the law for prevention of risks at work published in the official state Gazette (BOE) on Friday 10th November 1995, BOE number 269, and the ‘‘Real Decreto’’ regarding health prevention against ionizing radiation published on Thursday 26th July 2001, BOE number 178. Before blood

Address for correspondence: Unitat d’Antropologia, Dpt. Biologia Animal, Biologia Vegetal i Ecologia, Facultat de Cie`ncies, Universitat Auto`noma de Barcelona, E-08193, Bellaterra, Spain; e-mail: francesc. barquinero@uab.es. 1

612


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.