Comparative study of micronucleus assays and dicentric plus ring chromosomes for dose assessment in particular cases of partial-body exposure

Abstract

Purpose: The goal was to compare the micronucleus (MN) and dicentric plus ring chromosomes (D + R) assays for dose assessment in cases of partial body irradiations (PBI).

Materials and methods: We constructed calibration curves for each assay at doses ranging from 0 to 5 Gy of X-rays at dose rate of 0.275 Gy/min. To simulate partial-body exposures, blood samples from two donors were irradiated with 0.5, 1, 2 and 4 Gy and the ratios of irradiated to unirradiated blood were 25, 50, and 100%. Different tests were used to confirm if all samples were overdispersed or zero-inflated and for partial-body dose assessment we used the Qdr, Dolphin and Bayesian model.

Results: In our samples for D + R calibration curve, practically all doses agreed with Poisson assumption, but MN exhibited overdispersed and zero-inflated cellular distributions. The exact Poisson tests and zero-inflated tests demonstrate that virtually all samples of D + R from PBI simulation fit the Poisson distribution and were not zero-inflated, but the MN samples were also overdispersed and zero-inflated. In the partial-body estimation, when Qdr and Dolphin methods were used the D + R results were better than MN, but the doses estimation defined by the Bayesian methodology were more accurate than the classical methods.

Conclusions: Dicentric chromosomes continue to prove to be the best biological marker for dose assessment. However exposure scenarios of partial-body estimation, overdispersion and zero-inflation may not occur, it being a critical point not only for dose assessment, but also to confirm partial-body exposure. MN could be used as alternative assay for partial-body dose estimation, but in case of an accident without any information, the MN assay could not define whether the accident was a whole-body irradiation (WBI) or a PBI.

Keywords:

• Dicentrics
• micronucleus
• partial-body estimation
• zero-inflation

Disclosure statement

The authors declare that there are no conflicts of interest.

Additional information

Funding

This work was conducted during a scholarship supported by the Program CAPES/DS 1499445 at the Federal University of Pernambuco. Financed by CAPES – Brazilian Federal Agency for Support and Evaluation of Graduate Education within the Ministry of Education of Brazil and also was supported by the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy through the 0650.0650 - Research & Development in Healthy Project.

Notes on contributors

Mariana E. Mendes

Mariana E. Mendes, doctoral student at the Departamento de Genética, Universidade Federal de Pernambuco, Recife, Brazil and collaborator in Laboratory of Biological Dosimetry of the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil.

Julyanne C. G. Mendonça

Julyanne C. G. Mendonça, Master, collaborator in Laboratory of Biological Dosimetry of the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil

Joan F. Barquinero

Joan F. Barquinero, PhD, is a Full Professor (Docent) of Human Genetics and Senior Researcher at the Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Autonomous University of Barcelona, Cerdanyola del Vallès, Spain.

Manuel Higueras

Manuel Higueras, PhD, is an associate professor within the Mathematics and Computation Department at the La Rioja University.

Jorge E. Gonzalez

Jorge E. Gonzalez, pharmacist, is the head of radiobiology laboratory at the Center for Radiation Protection and Hygiene (CPHR) of Cuba.

Aida M. G. Andrade

Aida M. G. Andrade, master student at the Departamento de Genética, Universidade Federal de Pernambuco, Recife, Brazil.

Laís M. Silva

Laís M. Silva, collaborator in Laboratory of Biological Dosimetry of the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil.

Alyne M. S. Nascimento

Alyne M. S. Nascimento, collaborator in Laboratory of Biological Dosimetry of the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil.

Julianne C. F. Lima

Julianne C. F. Lima, collaborator in Laboratory of Biological Dosimetry of the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil.

Júlio C. G. Silva

Júlio C. G. Silva, collaborator in Laboratory of Biological Dosimetry of the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil.

Suy Hwang

Suy Hwang, biologist, is the substitute head of the Laboratory of Biological Dosimetry of the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil.

Ana M. M. A. Melo

Ana M. M. A. Melo, PhD, is a Full Professor (Docent) at Department of Biophysics and Radiobiology, Federal University of Pernambuco, Recife, Brazil.

Neide Santos

Neide Santos, PhD, is a Full Professor (Docent) at Department of Genetic, Federal University of Pernambuco, Recife, Brazil.

Fabiana F. Lima

Fabiana Lima, physicist, is the head of the Laboratory of Biological Dosimetry at the Regional Center of Nuclear Sciences of the Northeast (CRCN-NE), linked to the National Commission of Nuclear Energy, Brazil.