Theoretical increase of thyroid cancer induction from cervical spine multidetector computed tomography in pediatric trauma patients.

Abstract

The trend of increasing cervical spine multidirectional computed tomography (MDCT) imaging of pediatric trauma patients is characteristic of the overall dramatic increase in computed tomography utilization in the United States. The purpose of this study is to compare the amount of radiation a pediatric trauma patient absorbs to the thyroid from plain radiographs and MDCT of the cervical spine and to express risk by calculation of theoretical thyroid cancer induction. A retrospective evaluation of pediatric trauma patients admitted from October 1, 2004, to October 31, 2009, was performed at an academic, Level I trauma center. Inclusion criteria were Level I/II trauma patients, cervical spine imaging performed at our institution, and age <18 years. Absorbed thyroid radiation was calculated for patients receiving plain radiographs or MDCT. Thyroid cancer risk was calculated using the 2006 Biological Effects on Ionizing Radiation VII report. Six hundred seventeen patients met inclusion criteria: 224 received cervical spine radiographs and 393 received cervical spine MDCT. The mean thyroid radiation absorbed from radiographs was 0.90 mGy for males and 0.96 mGy for females compared with 63.6 mGy (males) and 64.2 mGy (females) receiving MDCT (p < 0.001). The median excess relative risk of thyroid cancer induction from one cervical spine MDCT in males was 13.0% and females was 25.0%, compared with 0.24% (males) and 0.51% (females) for radiographs (p < 0.001). The significant difference in radiation that MDCT delivers to the pediatric trauma patient when compared with plain radiographs should temper routine use of computed tomography in pediatric cervical spine clearance algorithms.