Bärenfänger Felix, Block Andreas, Rohde Stefan
Department of Experimental Physics 5, TU Dortmund, Germany.
Department of Medical Radiation Physics and Radiation Protection, Hospital of Dortmund gGmbH, Dortmund, Germany.
Rofo. 2019 Dec;191(12):1099-1106. doi: 10.1055/a-0924-5945. Epub 2019 Jul 24.
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.
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 (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.
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.
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 (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.
· In 64 % of the thrombectomies the skin equivalent doses were in the harmless range (< 1 Gy).. · In 6 % of the patients higher H P(0.07) values were determined, which can lead to deterministic radiation damage to the skin.. · To avoid deterministic damage during neurointerventions, H P(0.07) should be recorded (combined measuring chambers).. · For longer interventions, precautions should be taken to reduce the radiation dose..
· Bärenfänger F, Block A, Rohde S. Investigation of Radiation Exposure of Patients with Acute Ischemic Stroke during Mechanical Thrombectomy. Fortschr Röntgenstr 2019; 191: 1099 - 1106.
在放射介入治疗中，皮肤是最易受辐射的器官。本研究旨在调查接受机械取栓术患者的局部剂量暴露情况以及由此产生的确定性辐射效应风险。
本研究评估了2016年9月至2017年4月期间连续50例接受机械取栓术的中风患者的检查方案。所有手术均在双平面血管造影设备上进行。使用记录的辐射数据和先前测量的转换因子，回顾性计算局部皮肤等效剂量（0.07）。根据辐射质量，在Alderson-Rando头部模型表面使用硅半导体探测器进行转换因子的体外测定。
血管闭塞位于大脑中动脉M1和M2段（n = 32）、颈内动脉或颈总动脉（n = 12）以及基底动脉（n = 6）。透视时间从5.7分钟到137.3分钟不等，平均值为39.5±4.1分钟。测定的皮肤等效剂量值范围为0.16±0.02 Gy至4.80±0.51 Gy，平均值为1.00±0.14 Gy。在50例病例中有3例（6%）超过了德国辐射防护委员会公布的皮肤反应阈值3 Gy。另有15例患者（36%）接受了1 - 3 Gy的剂量。在后循环闭塞和颈动脉闭塞的长时间手术中达到了最高剂量值。此外，可为我们中心的机械取栓术中皮肤等效剂量确定局部剂量参考水平为1.24±0.15 Gy。
即使在现代神经放射介入治疗（如机械取栓术）过程中，也会产生对患者的辐射剂量，并且在大约6%的病例中可能导致皮肤的确定性辐射损伤。对局部剂量量（如0.07）进行系统监测似乎是合适的。介入团队应与医学物理专家合作，开发记录和降低局部剂量负荷的方法。
· 在64%的取栓术中，皮肤等效剂量处于无害范围（<1 Gy）。· 在6%的患者中确定了较高的H P(0.07)值，这可能导致皮肤的确定性辐射损伤。· 为避免神经介入治疗期间的确定性损伤，应记录H P(0.07)（组合测量室）。· 对于较长时间的介入治疗，应采取预防措施降低辐射剂量。
· Bärenfänger F, Block A, Rohde S. Investigation of Radiation Exposure of Patients with Acute Ischemic Stroke during Mechanical Thrombectomy. Fortschr Röntgenstr 2019; 191: 1099 - 1106.
