title: DNA double-strand breaks as potential indicators for the biological effects of ionising radiation exposure from cardiac CT and conventional coronary angiography: a randomised, controlled study.
abstract: OBJECTIVE
  To prospectively compare induced DNA double-strand breaks by cardiac computed tomography (CT) and conventional coronary angiography (CCA).
  
  
  METHODS
  56 patients with suspected coronary artery disease were randomised to undergo either CCA or cardiac CT. DNA double-strand breaks were assessed in fluorescence microscopy of blood lymphocytes as indicators of the biological effects of radiation exposure. Radiation doses were estimated using dose-length product (DLP) and dose-area product (DAP) with conversion factors for CT and CCA, respectively.
  
  
  RESULTS
  On average there were 0.12 ± 0.06 induced double-strand breaks per lymphocyte for CT and 0.29 ± 0.18 for diagnostic CCA (P < 0.001). This relative biological effect of ionising radiation from CCA was 1.9 times higher (P < 0.001) than the effective dose estimated by conversion factors would have suggested. The correlation between the biological effects and the estimated radiation doses was excellent for CT (r = 0.951, P < 0.001) and moderate to good for CCA (r = 0.862, P < 0.001). One day after radiation, a complete repair of double-strand breaks to background levels was found in both groups.
  
  
  CONCLUSIONS
  Conversion factors may underestimate the relative biological effects of ionising radiation from CCA. DNA double-strand break assessment may provide a strategy for individualised assessments of radiation.
  
  
  CONCLUSIONS
  • Radiation dose causes concern for both conventional coronary angiography and cardiac CT. • Estimations of the biological effects of ionising radiation may become feasible. • Fewer DNA double-strand breaks are induced by cardiac CT than CCA. • Conversion factors may underestimate the relative effects of ionising radiation from CCA.
authors.affiliation: Department of Radiology, Charité Medical School, Berlin, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Geisel
authors.forename: Elke
authors.initials: E
authors.lastname: Zimmermann
authors.forename: Matthias
authors.initials: M
authors.lastname: Rief
authors.forename: Johannes
authors.initials: J
authors.lastname: Greupner
authors.forename: Michael
authors.initials: M
authors.lastname: Laule
authors.forename: Fabian
authors.initials: F
authors.lastname: Knebel
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamm
authors.forename: Marc
authors.initials: M
authors.lastname: Dewey
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization; D017023:Coronary Angiography / Q000009:adverse effects*; D053903:DNA Breaks, Double-Stranded; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008214:Lymphocytes / Q000000981:diagnostic imaging / Q000528:radiation effects; D008297:Male; D008856:Microscopy, Fluorescence / Q000379:methods; D008875:Middle Aged; D011829:Radiation Dosage; D011839:Radiation, Ionizing; D012062:Relative Biological Effectiveness; D014057:Tomography, X-Ray Computed / Q000009:adverse effects*