Di Rosso Jana, Krasser Andreas, Tschauner Sebastian, Guss Helmuth, Sorantin Erich
Division of Paediatric Radiology, Department of Radiology, Medical University of Graz, 8036 Graz, Austria.
Competence Centre for Medical Physics and Radiation Protection, University Hospital Graz, 8036 Graz, Austria.
J Clin Med. 2023 Dec 20;13(1):25. doi: 10.3390/jcm13010025.
Cranial CT scans are associated with radiation exposure to the eye lens, which is a particularly radiosensitive organ. Children are more vulnerable to radiation than adults. Therefore, it is essential to use the available dose reduction techniques to minimize radiation exposure. According to the European Consensus on patient contact shielding by the IRCP from 2021, shielding is not recommended in most body areas anymore. This study aims to evaluate whether bismuth shielding as well as its combination with other dose-saving technologies could still be useful. Cranial CT scans of a pediatric anthropomorphic phantom were performed on two up-to-date MDCT scanners. Eye lens dose measurements were performed using thermoluminescent dosimeters. Furthermore, the impact of BS and of the additional placement of standoff foam between the patient and BS on image quality was also assessed. Bismuth shielding showed a significant lens dose reduction in both CT scanners (GE: 41.50 ± 4.04%, < 0.001; Siemens: 29.75 ± 6.55%, = 0.00). When combined with AEC, the dose was lowered even more (GE: 60.75 ± 3.30%, < 0.001; Siemens: 41.25 ± 8.02%, = 0.00). The highest eye dose reduction was achieved using BS + AEC + OBTCM (GE: 71.25 ± 2.98%, < 0.001; Siemens: 58.75 ± 5.85%, < 0.001). BS caused increased image noise in the orbital region, which could be mitigated by foam placement. Eye shielding had no effect on the image noise in the cranium. The use of BS in cranial CT can lead to a significant dose reduction, which can be further enhanced by its combination with other modern dose reduction methods. BS causes increase in image noise in the orbital region but not in the cranium. The additional use of standoff foam reduces image noise in the orbital region.
头颅CT扫描会使眼晶状体受到辐射，而眼晶状体是一个对辐射特别敏感的器官。儿童比成人更容易受到辐射影响。因此，使用现有的剂量降低技术以尽量减少辐射暴露至关重要。根据2021年国际辐射防护委员会（IRCP）关于患者接触屏蔽的欧洲共识，在大多数身体部位不再建议进行屏蔽。本研究旨在评估铋屏蔽及其与其他剂量节省技术的组合是否仍然有用。在两台最新的多层螺旋CT（MDCT）扫描仪上对一个儿科人体模型进行头颅CT扫描。使用热释光剂量计进行眼晶状体剂量测量。此外，还评估了铋屏蔽（BS）以及在患者与铋屏蔽之间额外放置间隔泡沫对图像质量的影响。铋屏蔽在两台CT扫描仪中均显示出眼晶状体剂量显著降低（通用电气公司：41.50±4.04%，P<0.001；西门子公司：29.75±6.55%，P = 0.00）。当与自动曝光控制（AEC）结合使用时，剂量降低得更多（通用电气公司：60.75±3.30%，P<0.001；西门子公司：41.25±8.02%，P = 0.00）。使用BS + AEC + 优化的束流调制（OBTCM）实现了最高的眼剂量降低（通用电气公司：71.25±2.98%，P<0.001；西门子公司：58.75±5.85%，P<0.001）。铋屏蔽导致眼眶区域图像噪声增加，这可通过放置泡沫来减轻。眼部屏蔽对颅骨区域的图像噪声没有影响。在头颅CT中使用铋屏蔽可导致显著的剂量降低，通过与其他现代剂量降低方法结合可进一步增强。铋屏蔽会导致眼眶区域图像噪声增加，但不会导致颅骨区域图像噪声增加。额外使用间隔泡沫可降低眼眶区域的图像噪声。
