Evaluation of Radiation Doses and Dose Conversion Coefficients for Pediatric Cardiac Catheterization Procedures

Pediatric cardiac catheterization covers both diagnostic and therapeutic procedures that range from simple to complex and can subject pediatric patients to varying radiation doses. There is limited information on radiation doses delivered by pediatric cardiac catheterization procedures and there is no recommended reference dose levels established yet. The study aims to determine the variation in patient radiation doses in terms of dose area product values and effective doses; determine factors that contribute to high doses to optimize protection; and determine the effective dose conversion coefficient. It is also aimed to provide data to help in the establishment of reference dose levels. A total of 761 pediatric patients belonging to age groups 0, 1, 5 and 10 years who undergo diagnostic and three selected therapeutic procedures at King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia are included in the study. Therapeutic procedures include COA, PDA and pulmonary procedures. Fluoroscopy and cine radiography are used in all procedures. Patient demography (weight, age, gender and height), radiographic technique factors, fluoroscopy and cine time, frame rate, and dose area product values are taken from patients records. Results show that the kVp varies by ± 1 kVp between procedures and by ± 6 kVp between AP and oblique + lateral projection for all procedures. The mA for lateral and oblique is about 40-70% higher than for AP. Effective doses for each procedure are estimated from the DAP values. The mean DAP and effective dose per procedure are analyzed for correlation with patient equivalent cylindrical diameter, weight, fluoroscopy time and number of frames. Initial results show that age group 0 and 1 year old have the highest mean value for effective dose (11.3 and 13.8 mSv respectively) for pulmonary procedure. Pooling all ages for each procedure, the pulmonary and PDA procedures gave the highest mean values for effective dose (10 and 8.2 mSv respectively) and DAP (1055 and 1048 cGy-cm respectively). An effective dose conversion coefficient of 120 cGy-cm per mSv was obtained when all ages were pooled for all procedures.