Assessment of radiation dose to pediatric patients during routine digital chest X-ray procedure in a government medical centre in Asaba, Nigeria

Abstract

Objective: Radiation dose to pediatric patients have been widely reported, it is however necessary that imaging expert keep doses as low as possible to forestall stall long term cancer risk. This study is aimed at determining pediatric entrance surface dose (ESD), 75th percentile ESD, absorbed dose (D) and effective dose (E) for 0-15 years.
 Material and Methods: The study used a digital radiography (DR) unit with a grid system for each chest X-ray. The thermoluminescent dosimeter (TLD) used was encapsulated in transparent nylon, it was then attached to the patient skin (chest wall) and the second was placed directly at the posterior end of it.
 Results: The mean ESDs for the 4 age groups were as follows: 0- < 1 (1.54±0.74mGy), 1- < 5 (1.53±0.83mGy), 5- < 10 (0.55±0.39mGy) and 10- ≤15 (1.30±0.57mGy), with an overall mean of 1.23mGy. The 75th percentile ESD for each age group above 10 patients (excluding 5- < 10yrs) was 2.18, 2.19 and 1.75mGy respectively. The absorbed dose (D) ranged from 0.03-2.39mGy. The mean effective dose (E) for the 4 age groups was 0.18±0.03mSv. There was a good correlation between ESD and D (P = 0.001). A One-Way ANOVA shows that the field size and focus to film distance (FFD) affected the ESD and D (P < 0.001) respectively. The risk of childhood cancer from a single radiograph was of the order of (1.54-23.4) ×10-6.
 Conclusion: The 75th percentile ESD, E and childhood risk of cancer was higher than most studies it was compared with. The study reveals that machine parameters such as the field size and FFD played a major role in dose increase. Protocol optimization is currently needed for pediatric patients in the studied facility.