title: Dose-Response Curves of theFDXRandRAD51Genes with 6 and 18 MV Beam Energies in Human Peripheral Blood Lymphocytes.
abstract: BACKGROUND
  Rapid dose assessment using biological dosimetry methods is essential to increase the chance of survival of exposed individuals in radiation accidents.
  
  
  OBJECTIVE
  We compared the expression levels of theFDXRandRAD51genes at 6 and 18 MV beam energies in human peripheral blood lymphocytes. The results of our study can be used to analyze radiation energy in biological dosimetry.
  
  
  METHODS
  For this in vitro experimental study, from 36 students in the medical physics and virology departments, seven voluntary, healthy, non-smoking male blood donors of Khuzestan ethnicity with no history of exposure to ionization radiation were selected using simple randomized sampling. Sixty-three peripheral blood samples were collected from the seven healthy donors. Human peripheral blood was then exposed to doses of 0, 0.2, 0.5, 2, and 4 Gy with 6 and 18 MV beam energies in a Linac Varian 2100C/D (Varian, USA) at Golestan hospital in Ahvaz, Iran. After RNA extraction and cDNA synthesis, the expression levels ofFDXRandRAD51were determined 24 hours post-irradiation using the gel-purified reverse transcription polymerase chain reaction (RT-PCR) technique and TaqMan strategy (by real-time PCR).
  
  
  RESULTS
  The expression level ofFDXRgene was significantly increased at doses of 2 Gy and 4 Gy in the 6 - 18 MV energy range (P < 0.001 and P < 0.008, respectively). The medians with interquartile ranges (IQRs) of the copy numbers of theFDXRgene at 2 Gy and 4 Gy doses under 6 and 18 MV beam energies were 2393.59 (1798.21, 2575.37) and 2983.00 (2199.48, 3643.82) and 3779.12 (3051.40, 5120.74) and 5051.26 (4704.83, 5859.17), respectively. However,RAD51gene expression levels only showed a significant difference between samples at a dose of 2 Gy with 6 and 18 MV beam energies, respectively (P < 0.040). The medians with IQRs of the copy numbers of theRAD51gene were 2092.77 (1535.78, 2705.61) and 3412.57 (2979.72, 4530.61) at beam energies of 6 and 18 MV, respectively.
  
  
  CONCLUSIONS
  The data suggest that the expression analysis of theFDXRgene, contrary to that of theRAD51gene, may be suitable for assessment of high-energy X-ray. In addition,RAD51is not a suitable gene for dose assessment in biological dosimetry.
authors.affiliation: Department of Medical Genetics, Faculty of Medicine, Ahvaz Jundishapour University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Alihossein
authors.initials: A
authors.lastname: Saberi
authors.affiliation: Department of Radiology and Nuclear Medicine, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Khodamoradi
authors.affiliation: Department of Radiology and Nuclear Medicine, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Tahmasebi Birgani
authors.affiliation: Department of Virology, Faculty of Medicine, Ahvaz Jundishapour University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Manoochehr
authors.initials: M
authors.lastname: Makvandi
authors.affiliation: Social Determinants of Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, IR Iran.
authors.forename: Bijan
authors.initials: B
authors.lastname: Noori
keywords: Dose-Response Relationship; Lymphocytes; X-Rays