Decreasing the radiation dose in paediatric cardiac catheterisation- Removal of scatter radiation : a randomised controlled clinical trial.

ABSTRACT: The number of paediatric interventional radiology (IR) procedures being performed hasincreased rapidly in recent years. Interventional procedures have been reported to contribute to the highestdoses of radiation to patients from medical examinations. It is imperative that we strive to reduce theradiation burden to our radiosensitive paediatric patients. Previous work has reported a wide variation ofimaging protocols currently being used in the UK and Ireland. These variations in practice are having asignificant impact on the resultant radiation dose to the patient.· Aim: To investigate the effect of different scatter removal techniques on radiation dose and associatedDNA damage by quantifying γH2AX-foci as a biomarker of radiation-induced effect.· Methods: An RCT was implemented in one specialised IR suite in Northern Ireland. Children were imagedusing either: (i) an anti-scatter grid (current departmental protocol), (ii) no anti-scatter grid or, (iii) no anti-scatter grid and a 15 cm air-gap between the child and the x-ray detector. Dose area product and imagequality were assessed, lifetime attributable cancer risk estimates were calculated and DNA double-strandbreakages quantified using the γH2AX assay.· Results: Consent was obtained from 70 parents/guardians/children. Patients were randomly allocated intothe 3 different techniques for the examinations performed. Image quality was sufficient for each procedureperformed. Removal of the anti-scatter grid resulted in dose reductions of 20% (no anti-scatter grid) and30% (15 cm air-gap), DNA double-strand break reductions of 30% (no anti-scatter grid) and 20% (15 cmair-gap) and a reduction of radiation-induced cancer mortality risk of up to 45%.· Conclusion: Simple modifications to technique can be easily implemented by the radiographer. It is feasibleto remove the anti-scatter grid resulting in a reduction in DNA damage to the patient. This will ensure theradiation dose to paediatric patients is kept ALARA without affecting image quality or diagnostic efficacy.The γH2AX assay may be used for assessment of dose optimisation strategies in children