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

Eur Radiol. 2012 Aug;22(8):1641-50. doi: 10.1007/s00330-012-2426-1. Epub 2012 Apr 17.


Objectives: 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.

Key points: • 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.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Cardiac Catheterization
  • Coronary Angiography / adverse effects*
  • DNA Breaks, Double-Stranded*
  • Dose-Response Relationship, Radiation
  • Female
  • Heart / diagnostic imaging*
  • Humans
  • Lymphocytes / diagnostic imaging
  • Lymphocytes / radiation effects
  • Male
  • Microscopy, Fluorescence / methods
  • Middle Aged
  • Radiation Dosage
  • Radiation, Ionizing
  • Relative Biological Effectiveness
  • Tomography, X-Ray Computed / adverse effects*