Author: Dean Darnell, Iyanna M Lewis, Francesco Ria, William Paul Segars 👨🔬
Affiliation: Duke University, Duke University Medical Physics Graduate Program, Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories and Center for Virtual Imaging Trials, Duke University Medical Center, Duke University Medical Center 🌍
Purpose: To estimate radiation dose to pediatric patients during standard CT imaging of the chest and abdomen and determine how dose varies with patient age, height and weight and how measurements compare to doses estimated from the reference phantoms of the International Commission on Radiation Protection (ICRP).
Methods: We utilized the pediatric series of 4D extended cardiac-torso (XCAT) phantoms consisting of 64 unique, whole-body models. Each phantom was constructed based on CT data from Duke University Hospital of male and female pediatric patients between 2 months and 18 years old. The XCAT phantoms were virtually imaged and organ doses estimated using the DukeSim CT image simulator using standard protocols for the chest and abdomen. The dose estimates were analyzed and compared to those of the standard reference computational phantoms developed by the ICRP.
Results: The XCAT phantoms show a range of variability in organ doses for each age group compared to their corresponding reference phantom. For example, female patients between the ages of 14–16 show a difference in average dose of up to 13% compared to the 15-year-old reference phantom. However, when analyzing organ doses in relation to body mass index (BMI) rather than by age alone, the relationship appears more linear.
Conclusion: The results of this study demonstrate the overall variation of CT imaging organ dose estimates of pediatric phantoms of varying ages from their closest corresponding reference phantom. These findings suggest that alternative phantoms incorporating BMI or other patient parameters should be considered, instead of relying solely on age.