Comparison of the radiation exposure of patients caused by selected interventional and angiographic procedures - initial results

Purpose: To determine and judge patient doses caused by selected interventional and angiographic procedures using the 'Multiskop' digital C-arm unit. Materials and methods: The dose-area product and the fluoroscopic time were measured for 71 percutaneous transluminal angioplasties (PTA), 33 PTA with stent implantation, and 37 embolisations; in addition, they were also measured for 285 digital subtraction angiographies (DSA). In the case of 13 PTA, 10 embolisations, and 33 DSA the number of radiographs was determined, and the dose-area product was divided into two parts, fluoroscopy and radiography, applying a computer programme. Results: The median values of the dose-area product and the fluoroscopic time amounted to 36 Gy cm2 and 11.5 min for PTA, 131 Gy cm2 and 14.4 min for PTA with stent implantation, 197 Gy cm2 and 24.5 min for embolisation as well as 87 Gy cm2 and 3.7 min for DSA. For the relation between dose-area products caused by fluoroscopy and radiography and the number of radiographs median values of 0.67 and 70 for PTA, 0.58 and 153 for embolisation as well as 1.35 and 135 for DSA were determined. Conclusion: To reduce the relatively high patient doses the modification of the C-arm unit is aspired to realize pulsed fluoroscopy and automatic filter selection. Also experimental investigations will be done related to additional filtration and reduction of the image intensifier input dose rate and dose per frame, respectively. Then the effect of dose reduction caused by these measures will be confirmed in a comparable patient study. (orig.)