Cumulative Radiation Exposure and Cancer Risk Estimation in Children with Heart Disease

C hildren with congenital and acquired heart disease typically undergo imaging procedures that may expose them to large amounts of ionizing radiation. Radiation exposure in childhood is of particular concern because children have immature developing organ and tissue structures. These factors , as well as the potentially longer lifespan of these children , may significantly increase lifetime cancer risk. Previous studies of radiation exposure in children have largely focused on single exposure from various imaging modalities, including computed tomography (CT), fluoros-copy, nuclear medicine, and radiographs. ; however, children with complex heart diseases are often exposed to repetitive imaging. 16 According to current guidelines from the International Committee on Radiation Protection, stochastic exposure risks (ie, cancer) increase in a linear, dose-response fashion, and therefore, repetitive exposures are believed to incrementally increase risk. 17 What is currently unknown in young children with heart disease is the amount of cumulative exposure, the relative contribution of various imaging modalities to cumulative exposure, and the associated lifetime attributable risk (LAR) of cancer. In a cohort of young children undergoing 1 of 7 operations for congenital and acquired heart disease, we sought to estimate (1) the cumulative effective dose of radiation exposure across the spectrum of radiation-producing imaging modalities ; (2) the relative contribution of various imaging modalities to cumulative effective dose; and (3) the estimated LAR of cancer from cumulative radiation exposure. Background—Children with heart disease are frequently exposed to imaging examinations that use ionizing radiation. Although radiation exposure is potentially carcinogenic, there are limited data on cumulative exposure and the associated cancer risk. We evaluated the cumulative effective dose of radiation from all radiation examinations to estimate the lifetime attributable risk of cancer in children with heart disease. Methods and Results—Children ≤6 years of age who had previously undergone 1 of 7 primary surgical procedures for heart disease at a single institution between 2005 and 2010 were eligible for the study. Exposure to radiation-producing examinations was tabulated, and cumulative effective dose was calculated in millisieverts. These data were used to estimate lifetime attributable risk of cancer above baseline using the approach of the Committee on Biological Effects of Ionizing Radiation VII. The cohort included 337 children exposed to 13 932 radiation examinations. Conventional radiographs represented 92% of examinations, whereas cardiac catheterization and computed tomography accounted for 81% of cumulative exposure. Overall median cumulative effective dose was 2.7 mSv (range, 0.1–76.9 mSv), and the associated …