Optimization of beam filtering, kV-mA regulation curve, and image intensifier entrance exposure rate to reduce radiation exposure in angiographic fluoroscopy.

Aim of study: Evaluation of radiation exposure and image quality during flu oroscopy using a new vascular X-ray system. Material and methods: The measu rements were made on an Integris V 3000 X-ray system with MRC tube and Spec traBeam technology (Philips Medical Systems, Hamburg). Entrance dose rates were measured with phantoms for the three fluoroscopy levels (1-3) which di ffered with regard to beam filtering and image intensiver entrance exposure rate. We evaluated 132 diagnostic and interventional angiographic studies. The angiographic investigators were asked to start with level 1 and to cha nge to the next fluoroscopy level only in the case of insufficient image qu ality. Results: Entrance dose rate is reduced by approx. 74% at fluoroscopy level 1 and by approx. 46% at level Z relative to level 3 which is compara ble to angiographic X-ray systems without MRC tube and SpectraBeam technolo gy. Because level 1 ensured a sufficient image quality in 92% of the diagno stic and 60% of the interventional angiographic procedures a change to high er fluoroscopy levels was not necessary. Conclusion: Reduction of the inten sifier exposure rate and the optimization of beam filtering enabled us to r educe the radiation exposure considerably. The procedure was well accepted by the angiographic investigators due to the diagnostically sufficient imag e quality of the fluoroscopy level 1.