Estimation of dose and cancer risk to newborn from chest X ray in South South Nigeria: a call for protocol optimization
Background The use of X ray as a diagnostic tool for complication and anomaly in the neonatal patient has been helpful, but the effect of radiation on newborn stands to increase their cancer risk. This study aims to determine the mean, 50th percentile (quartile 2 (Q2) and 75th percentile (quartile 3 (Q3) entrance surface dose (ESD) from anteroposterior (AP) chest X ray and to compare our findings with other relevant studies. The study used calibrated thermoluminescent dosimeters (TLDs) which was positioned on the central axis of the patient. The encapsulated TLD chips were held to the patients' body using paper tape. The mean kilovoltage peak (kVp) and milliampere seconds (mAs) used was 56.63(52 60) and 5.7 (5 6.3) The mean background TLD counts were subtracted from the exposed TLD counts and a calibration factor was applied to determine ESD. Results The mean ESDs of the newborn between 1 and 7, 8 and 14, 15 and 21, and 22 and 28 days were 1.09 0.43, 1.15 0.50, 1.19 0.45, and 1.32 0.47 mGy respectively. A one way ANOVA test shows that there were no differences in the mean doses for the 4 age groups P 0.597) The 50th percentile for the 4 age groups was 1.07, 1.26, 1.09, and 1.29 mGy respectively, and 75th percentile were 1.41, 1.55, 1.55, and 1.69 mGy respectively. The mean effective dose (ED) in this study was 0.74 mSv, and the estimated cancer risk was 20.7 x 10 6 Conclusion ESD was primarily affected by the film focus distance (FFD) and the patient field size. The ESD at 75th percentile and ED in this study was higher compared to other national and international studies. The estimated cancer risk to a newborn was below the International Commission on Radiological Protection (ICRP) limit for fatal childhood cancer (2.8 x 10 2 Sv 1
Egyptian Journal of Radiology and Nuclear Medicine