Estimation of effective dose for children in interventional cardiology

Abstract

This study is devoted to the estimation of effective dose for children undergoing interventional cardiology examinations. The conversion coefficients (CC) from directly measured dose area product (DAP) value to effective dose (ED) were calculated within the approved effective dose assessment methodology (Guidelines 2.6.1. 2944-11). The CC, Ed K , [mSv / (Gy • cm 2 )] for newborn infants and children of 1, 5, 10 and 15 years old (main(range)) were calculated as 2.5 (1.8-3.2); 1.1 (0.8-1.3); 0.6 (0.4-0.7); 0.4 (0.3-0.5); and 0,22 (0,18-0,30) respectively. A special Finnish computer program PCXMC 2.0 was used for calculating the dose CC. The series of calculations were made for different values of the physical and geometrical parameters based on their real-existing range of values. The value of CC from DAP to ED were calculated for all pediatric age groups. This work included 153 pediatric interventional studies carried out in two hospitals of the city of St. Petersburg for the period of one year from the summer of 2015. The dose CC dependency from the patient’s age and parameters of the examinations were under the study. The dependence from the beam quality (filtration and tube voltage) and age of the patient were found. The younger is the patient, stronger is the filtration and higher is the voltage, the higher is the CC value. The CC in the younger (newborn) and older (15 years) age groups are different by the factor of 10. It was shown that the changes of the geometric parameters (in the scope of their real existing range) have small effect on the value of the effective dose, not exceed 30-50% allowable for radiation protection purpose. The real values of effective doses of children undergoing cardiac interventions were estimated. In severe cases, the values of ED can reach several tens of mSv.