Radiation exposure during videofluoroscopic swallowing studies in young children

Swallowing difficulties are best assessed by videofluoroscopic swallowing studies (VFSS). However, limiting radiation exposure is important, especially in young children. The purpose was to evaluate radiation dose in young children during VFSS, and to investigate factors associated with it.

Children with swallowing difficulty who underwent VFSS from February 2012 to July 2014 were recruited. Dose area product (DAP) and screening time were offered by the fluoroscopy machine, and effective dose was calculated from the DAP using a conversion coefficient published by the National Radiological Protection Board (NRPB-R262). The age, gender, height, weight, body mass index (BMI), body surface area (BSA), underlying disease of the subject children, and results of VFSS were investigated.

In 89 children (mean age 1.57 ± 2.17, 55 boys and 34 girls), mean effective dose was 0.29 ± 0.20 mSv, mean DAP was 2.41 ± 1.65 Gy cm², and mean screening time was 2.24 ± 0.99 min. The effective dose correlated with the screening time (r = 0.598, p < 0.001), age (r = 0.210, p = 0.049), height (r = 0.521, p < 0.001), weight (r = 0.461, p < 0.001), and BSA (r = 0.493, p < 0.001). There was no such correlation with gender, BMI, underlying disease, or the results of VFSS.

The effective dose during VFSS (0.29 mSv) in young children, which is affected by screening time, age, and body size, is considerably lower than the pediatric radiation exposure limit of 1 mSv per year. However more than 4 VFSS annually would exceed this limit. Our findings will help physicians to reduce the radiation exposure and provide a useful references for future pediatric VFSS guidelines.