Effective dose estimation for pediatric voiding cystourethrography using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology

Abstract

The risks associated with radiation exposure are higher in children than in adults. Therefore the use of fluoroscopy in common pediatric examinations such as voiding cystourethrography (VCUG) requires accurate determination of the associated effective dose. To estimate effective dose for VCUG examinations performed in children younger than 10 years using anthropomorphic phantoms and metal oxide semiconductor field-effect transistor (MOSFET) dosimeters. MOSFETs were placed within four phantoms representing children </=10 years old, at locations corresponding to radiosensitive organs, and exposed to a mock VCUG (5 min of fluoroscopy, 50 spot exposures) to minimize measurement error. Effective dose was measured and scaled to a standardized clinical VCUG (1 min fluoroscopy, 5 spot exposures) determined from patient logs. Monte Carlo simulations were performed to assess the accuracy of the measured effective dose. The dose area product (DAP) from each VCUG was compared to the effective dose. Effective doses ranged from 0.10 to 0.55 mSv, increased with age, and were higher in girls. Fluoroscopy accounted for 88-90% of the total effective dose, and spot exposures 10-12%. MOSFET-measured and simulation-derived effective doses were comparable (T > 0.12). DAP was strongly correlated with effective dose for both genders (r (2)>0.97, P < 0.0001). Effective doses for VCUG examinations performed in children <or=10 years of age are low but not negligible.