Cumulative patient effective dose and acute radiation-induced chromosomal DNA damage in children with congenital heart disease

BACKGROUND: The seventh Committee on "Biological effects of Ionizing Radiation" (BEIR VII, 2006) underlines "the need of studies of infants who are exposed to diagnostic radiation because catheters have been placed in their hearts". OBJECTIVE: To determine the Lifetime Attributable Risk (LAR) of cancer associated with the estimated cumulative radiological dose in 59 children (42 males, age=2.8±3.2 years) with complex CHD, and to assess chromosomal DNA damage after cardiac catheterization procedures. METHODS: In all patients, the cumulative exposure was estimated as effective dose in milliSievert (mSv), and LAR cancer was determined from BEIR VII report. In a subset of 18 patients (13 males, age: 5 2± 5.7 years) micronucleus (MN) as biomarker of DNA damage and long-term risk predictor of cancer was assayed before and 2 hours after catheterization procedures. Dose-area product (DAP; Gy cm2) was assessed as measure of patient dose. RESULTS: The median life time cumulative effective dose was 7.7 mSv per patient (range 4.6- 41.2 mSv). Cardiac catheterization procedures and computed tomography were responsible for 95% of the total effective dose. For a 1-year-old child, the LAR cancer was 1 in 382 (25th-75th percentiles 1 in 531-1 in 187) and 1 in 156 (25th-75th percentiles 1 in 239-1 in 83) for male and female patients, respectively. Median MN values increased significantly after procedure when compared to baseline (pre= 6 ? vs post= 9 ?, p=0.02). The median of DAP values was 20 Gy cm2 (range of 1-277 Gy cm2). CONCLUSION: CHD children are exposed to a significant cumulative dose. Both indirect cancer risk estimations and direct DNA data emphasize the need for strict radiation dose optimization in children.