Investigation of Radiation Exposure of Patients with Acute Ischemic Stroke during Mechanical Thrombectomy

Abstract

Purpose In radiological interventions, the skin is the most exposed organ. The aim of this study was to investigate the local dose exposure and the resulting risk of deterministic radiation effects for patients who underwent mechanichal thrombectomy. Materials and Methods The examination protocols of 50 consecutive stroke patients who underwent mechanical thrombectomy from September 2016 to April 2017 were evaluated in this study. All procedures were performed on a biplanar angiographic suite. The local skin equivalent dose H P(0.07) was calculated retrospectively using the recorded radiation data and previously measured conversion factors. The in-vitro determination of the conversion factors was performed with a silicon semiconductor detector on the surface of an Alderson-Rando head phantom depending on the radiation quality. Results Vessel occlusion was located in the M1 and M2 segments of the cerebral artery media (n = 32), the internal carotid artery or carotid-T (n = 12) and the basilar artery (n = 6). The fluoroscopy times ranged from 5.7 minutes to 137.3 minutes with an average value of 39.5 ± 4.1 minutes. The determined skin equivalent dose values ranged from 0.16 ± 0.02 Gy to 4.80 ± 0.51 Gy, with the mean value being 1.00 ± 0.14 Gy. In 3 out of 50 cases (6 %), the threshold value for skin reactions of 3 Gy published by the German Radiation Protection Commission was exceeded. A further 15 patients (36 %) were exposed to a dose of 1–3 Gy. The highest dose values were achieved during long procedures with occlusions in the posterior circulation and carotid occlusions. In addition, a local dose reference level of 1.24 ± 0.15 Gy could be determined for the skin equivalent dose in mechanical thrombectomies for our center. Conclusion Even during a modern neuroradiological intervention, such as mechanical thrombectomy, radiation doses to the patient are produced and can lead to deterministic radiation damage to the skin in approximately 6 % of cases. Systematic monitoring of local dose quantities, such as H P(0.07), seems appropriate. Possibilities for recording and reducing the local dose load should be developed by the interventional teams in cooperation with a medical physics expert. Key Points: Citation Format

Acute Endovascular Stroke Treatment in Germany in 2019

“…indicating that the mean time from symptom onset to the start of the intervention is about 75 min later in secondary referrals (Table 3). These findings can help in the discussion about stroke logistics in urban and more rural areas and-together with technical parameters like fluoroscopy time and dose-might be used as a helpful quality marker for the participating centers in the future [16].…”

Radiation exposure per thrombectomy attempt in modern endovascular stroke treatment in the anterior circulation

“…Likewise, fluoroscopy time increased per each additional thrombectomy attempt and was significantly different when comparing EST with one or two thrombectomy attempts (median (IQR), in minutes; FT 1 , 16 (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) and FT 2 , 26 (21-41), p value 0.001). An additional third, fourth, or fifth thrombectomy attempt led to a significant increase (FT 3 , 35 min (25-45), p value 2vs3 0.008; FT 4 , 49 min (32-76), p value 3vs4 0.0003; and FT 5 , 67 min (57-98), p value 4vs5 0.005).…”

“…The threshold for deterministic risks is reached in about 6% of ESTs while the relevance of the stochastic risk remains uncertain [12]. Although dose area products (DAPs) cannot be directly translated into local skin equivalent doses and should not be mistaken as an equivalent for deterministic risk, DAPs are an established metric to monitor and compare radiation exposure.…”

“…Monitoring radiation exposure of all stroke centers as a quality control is a practical tool to detect sources of systemically high radiation exposure. Recently, first data emerged to clarify the extent of radiation exposure in EST [12][13][14]. The number of thrombectomy attempts to recanalize an occluded target vessel is an essential parameter during EST defining the patient's clinical outcome [15][16][17].…”

Effect of treatment technique on radiation exposure in mechanical thrombectomy for acute ischaemic stroke: A matched-pair analysis

“…Approximately 6% of procedures reach the threshold of potential deterministic risk for the patient undergoing MT. 16 Additionally, cancer, premature cataracts, early cognitive impairment and premature vascular disease may affect staff working in a catheter laboratory. [17][18][19] As RE during MT depends on the interventionalist's experience, this might also imply a change in teaching strategy for future interventionalists.…”