Biological dosimetry of ionizing radiation: Evaluation of the dose with cytogenetic methodologies by the construction of calibration curves

Demetre Zafiropoulos,E Facco,Lucia Sarchiapone

doi:10.1142/s2010194516602398

Abstract

In case of a radiation accident, it is well known that in the absence of physical dosimetry biological dosimetry based on cytogenetic methods is a unique tool to estimate individual absorbed dose. Moreover, even when physical dosimetry indicates an overexposure, scoring chromosome aberrations (dicentrics and rings) in human peripheral blood lymphocytes (PBLs) at metaphase is presently the most widely used method to confirm dose assessment. The analysis of dicentrics and rings in PBLs after Giemsa staining of metaphase cells is considered the most valid assay for radiation injury. This work shows that applying the fluorescence in situ hybridization (FISH) technique, using telomeric/centromeric peptide nucleic acid (PNA) probes in metaphase chromosomes for radiation dosimetry, could become a fast scoring, reliable and precise method for biological dosimetry after accidental radiation exposures. In both in vitro methods described above, lymphocyte stimulation is needed, and this limits the application in radiation emergency medicine where speed is considered to be a high priority. Using premature chromosome condensation (PCC), irradiated human PBLs (non-stimulated) were fused with mitotic CHO cells, and the yield of excess PCC fragments in Giemsa stained cells was scored. To score dicentrics and rings under PCC conditions, the necessary centromere and telomere detection of the chromosomes was obtained using FISH and specific PNA probes. Of course, a prerequisite for dose assessment in all cases is a dose-effect calibration curve. This work illustrates the various methods used; dose response calibration curves, with 95% confidence limits used to estimate dose uncertainties, have been constructed for conventional metaphase analysis and FISH. We also compare the dose-response curve constructed after scoring of dicentrics and rings using PCC combined with FISH and PNA probes. Also reported are dose response curves showing scored dicentrics and rings per cell, combining PCC of lymphocytes and CHO cells with FISH using PNA probes after 10 h and 24 h after irradiation, and, finally, calibration data of excess PCC fragments (Giemsa) to be used if human blood is available immediately after irradiation or within 24 h.

Highlights

IntroductionDue to an increasing concern about accidental overexposures, as well as the threat of nuclear terrorism, the preparedness for medical management of radiation events is of great importance.[1,2] In the event that physical dosimetry-based dose estimates are unavailable or a high-dose dosimeter response has yet to be confirmed, the analysis of
Due to an increasing concern about accidental overexposures, as well as the threat of nuclear terrorism, the preparedness for medical management of radiation events is of great importance.[1,2] In the event that physical dosimetry-based dose estimates are unavailable or a high-dose dosimeter response has yet to be confirmed, the analysis ofThis is an Open Access article published by World Scientific Publishing Company
After gamma ray exposure with doses ranging from 0.3–5 Gy, a total of 6070 metaphases were manually analyzed, revealing 953 chromosomal aberrations (CA)

Summary

Introduction

Due to an increasing concern about accidental overexposures, as well as the threat of nuclear terrorism, the preparedness for medical management of radiation events is of great importance.[1,2] In the event that physical dosimetry-based dose estimates are unavailable or a high-dose dosimeter response has yet to be confirmed, the analysis of. This is an Open Access article published by World Scientific Publishing Company. Sarchiapone induced chromosomal aberrations (CA) at metaphase in the lymphocytes of peripheral blood (PBL) is the most valid technique.[3,4]

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