Abstract:

Aim: was to study the impact of angiographic projection on patient and operator radiation dose during endovascular interventions aimed at diagnosing and treating cerebrovascular diseases.

Materials and methods: in experiment, radiation dose rate of phantom model (cGy?cm²/s) and equivalent dose rate from scattered radiation (mSv/h) measured in the area of conditional location of operator were studied when the angle of the X-ray tube was changed in modes of digital subtraction angiography (DSA) and fluoroscopy. Radiation dose rate of endovascular surgeon (mSv/h) was assessed during 12 cerebral angiography procedures and 15 neuro-interventions in general angiographic projections. Values of the kerma-area product (Gy?cm²), fluoroscopy time (min), operator exposure dose (µSv) during 87 procedures of endovascular occlusion of aneurysm of cavernous and supraclinoid sections of internal carotid arteries (ICA) were retrospectively analyzed to indirectly assess the effect of angiographic projection on patient and surgeon occupational dose. Interventions were divided into 2 groups depending on the location of detected aneurysm. The 1st group included 35 operations in the right ICA, the 2nd group included 53 operations in the left ICA.

Results: in experimental study, highest values of radiation dose rate of the phantom model were found in frontal projection with cranial angulation, lowest - in lateral and oblique projections; The highest average dose rates from scattered radiation in operator's area were found in left lateral projections whereas the smallest in right lateral projection in DSA mode and also in frontal and right lateral projections in fluoroscopy mode.

When studying doses of scattered radiation during neuro-interventional procedures, it was found that when the position of the X-ray tube changes from 0° in the direction of left lateral projection, an increase in the average dose rate of the operator in the DSA mode is up to 2,6 times, with fluoroscopy - up to 2,4 times. The equivalent dose rate in left lateral projection is up to 1.5 times higher than in right lateral projection. In left oblique projection, there is an increase in dose rate up to 2,3 times compared to right oblique projection.When comparing radiation exposure indicators during aneurysm embolization procedures, a significant increase in operator exposure doses is observed in group of interventions in the left ICA.

Conclusion: when performing neuro-interventional procedures, it is possible to achieve a significant reduction in radiation exposure to patient and operator without a significant loss in image quality along with maintaining optimal visualization of pathological changes by choosing angiographic projections with lower radiation doses.

Abstract:

Article is devoted to a problem of radiation dose during multi-spiral computed tomograpy of abdominal cavity. This review describes the basic and additional methods of reducing the radiation exposure at CT with intravenous contrast enhancement. Results of researches conducted in recent years were considered and analyzed. Nuances of reduction of radiation exposure in specific cases were analyzed. Prospects of reducing the dose of contrast agent in abdominal MDCT with IV contrast media administration were estimated. The importance of control of radiation exposure of patients is proved.

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