title: Investigation of new cytogenetic biomarkers specific to high-LET radiation using in vivo and in vitro exposed human lymphocytes.
abstract: OBJECTIVE
  To find detectable cytogenetic biomarkers that can offer information about the radiation quality of in vivo exposure retrospectively.
  
  
  METHODS
  Chromosome-type aberrations of peripheral lymphocytes of uterine cancer patients that received internal gamma- and external X-ray therapy or carbon beam therapy and of victims severely exposed to neutrons and gamma-rays in a criticality accident that occurred in Tokai-mura, Japan were analysed. Data obtained from in vitro irradiation experiments using 60Co gamma-rays and 10 MeV neutrons were compared with the in vivo exposure data.
  
  
  RESULTS
  The ratio of acentric rings to dicentric chromosomes (termed RaD ratio) and that of excess fragments to dicentrics (termed EfD ratio) showed significant (p < 0.05) differences between the two groups of cancer patients, and these ratios for accidental victims were in between the values of the two groups of cancer patients. The in vitro studies using doses equivalent to 1 - 3 Gy of gamma-rays have confirmed that the EfD ratios were increased with the high LET (linear energy transfer) and RaD ratios decreased.
  
  
  CONCLUSIONS
  The present data show that the RaD and EfD ratios can be used as cytogenetic biomarkers of exposure to high-LET radiation at least within a few years of exposure.
authors.affiliation: Radiation Center for Radiation Protection, National Institute of Radiological Sciences, Anagawa, Chiba, Japan. kanda_r_nirs.go.jp
authors.forename: R
authors.initials: R
authors.lastname: Kanda
authors.forename: M
authors.initials: M
authors.lastname: Minamihisamatsu
authors.forename: S
authors.initials: S
authors.lastname: Tsuji
authors.forename: Y
authors.initials: Y
authors.lastname: Ohmachi
authors.forename: T
authors.initials: T
authors.lastname: Hiraoka
authors.forename: Y
authors.initials: Y
authors.lastname: Shimada
authors.forename: T
authors.initials: T
authors.lastname: Ogiu
authors.forename: T
authors.initials: T
authors.lastname: Ohno
authors.forename: I
authors.initials: I
authors.lastname: Hayata
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis*; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000528:radiation effects*; D002877:Chromosomes, Human / Q000528:radiation effects*; D020732:Cytogenetic Analysis / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D020450:Heavy Ions; D006801:Humans; D018499:Linear Energy Transfer; D008214:Lymphocytes / Q000528:radiation effects*; D008875:Middle Aged; D011829:Radiation Dosage; D018570:Risk Assessment / Q000379:methods*
chemical_list: D015415:Biomarkers