Scoring of Dicentrics
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closeup of slide showing normal metaphase spread of 46 chromosomes closeup of slide showing a dicentric spread of 45 chromosomes
Image AImage B

  • A digital photo of the metaphase spread is taken at 63x magnification.
  • A dicentric chromosome has two centromeres — the point where the two chromatids connect.
  • The number of dicentric chromosomes is counted and compared to calibration curves to estimate radiation dose.
  • Image A displays a normal metaphase spread.
  • Image B reveals a meatphase spread with a dicentric chromosome circled in red.

Adapted from Cytogenetic Biodosimetry Laboratory (Radiation Emergency Assistance Center/Training Site (REAC/TS))