[Evaluation of a low dose imaging protocol on radiation exposure reduction in pediatric supraventricular tachycardia...

Objective: To evaluate the feasibility and efficiency of a low dose imaging protocol on reducing X-ray dose level in pediatric supraventricular tachycardia (SVT) ablation procedure. Method: Data were collected from 103 patients who underwent catheter ablation for SVT in Children's Hospital of Fudan University from January 2014 to October 2016 in terms of body weight, body surface area (BSA), SVT types, accessory pathway location, fluoroscopy time and the radiation dose (including AIR KERMA and dose area product) in a case observational study.The fluoroscopy protocols were operated at 36 nGy/frame and 10 frames/s (Standard group, n=47) from January 2014 to September 2015, 36 nGy/frame and 10 frames/s with removal of the grid (Grid-out group, n=24) from October 2015 to April 2016, as well as 23 nGy/frame and 4.0-7.5 frames/s without the grid (Grid-out plus low dose group, n=32) from May 2016 to October 2016, respectively.Comparisons among groups were performed by independent-sample t-test or one-way analysis of variance for normally distributed continuous variables, and χ(2) test for categorical variables. Result: The average body weight, BSA, fluoroscopy time and AIR KERMA of the three groups was (34±14) kg, (1.14±0.33) m(2,) (11±8) minutes and (12.97±12.43) mGy, respectively.No significant differences in body weight (F=2.551), BSA (F=2.359), SVT types (χ(2)=6.15), and accessory pathway location (χ(2)=3.438) were observed among these three groups (P>0.05). Images acquired by low dose protocol could provide enough information for procedures, and no complication occurred.The acute success rates were 100% in all of these three groups, and there was no significant difference in mean fluoroscopy time (F=0.004, P>0.05) among them.However, the radiation dose (AIR KERMA) in the Grid-out plus low dose group was much lower than that in the Standard group ((7.54±7.31) mGy vs. (16.25±12.08) mGy, F=6.112, P<0.01)). Conclusion: The new strategy of combination of low dose fluoroscopy protocol with removal of grid markedly reduced radiation exposure to children undergoing supraventricular tachycardia ablation while maintaining procedural efficacy and safety.