中国攻克柔性高清乳腺成像关键技术
X线影像技术对于乳腺癌的早期筛查、早期诊断、治疗后随访和监测具有重要意义。不过，目前我国的高端X线影像设备及关键零部件主要依赖进口，制造大面积柔性薄膜晶体管阵列和非晶硅光电转换层也存在巨大的技术挑战，因此难以研制出柔性探测器，而采用刚性探测器不仅难以实现对乳房等高度弯曲或不规则物体的三维X线成像，并且与欧美女性相比，乳房相对较小的中国女性在检查过程中通常需要被反复用力挤压固定乳房而感到严重疼痛不适。
2021年2月17日，全球自然科学三大旗舰期刊之一、英国《自然》正刊发表中国福州大学、新加坡国立大学、香港理工大学、天津大学新加坡国立大学福州联合学院、中国福建光电信息科学与技术创新实验室、新加坡国立大学苏州研究院的研究报告，发现了一类高性能X线发光纳米闪烁体，通过结合光谱技术、电子顺磁共振特征、热释放光学曲线分析、密度泛函理论计算、同步辐射技术对晶格缺陷的本质展开研究，提出了高能量X线光子诱导缺陷产生长余辉发光的机理，该发光机制的建立对新型卤化物长余辉材料的探索与合成具有指导意义。
该研究表明，稀土镧系元素纳米晶闪烁体具有尺寸易调控、无色透明、分散性良好、余辉性能优异等特点，将其与柔性基底相结合，可制备出透明、可拉伸、无需电子电路的柔性X线成像设备，实现柔性、高分辨的全景X线成像，其成像空间分辨率大于每毫米20线对，并且光学存储时间超过15天。
因此，该研究打破了传统X线探测器的固有限制，为制备新一代柔性X线成像设备提供了新的思路和途径。基于纳米闪烁体的柔性X线成像设备具有制备工艺简单、便携式、成本低、成像性能优异等优势，对于便携式X线探测器、乳腺成像、牙科全景成像、工业探伤、高能物理等领域展现出巨大的潜力和应用价值。
Nature. 2021 Feb 17;590:410-415.
High-resolution X-ray luminescence extension imaging.
Xiangyu Ou, Xian Qin, Bolong Huang, Jie Zan, Qinxia Wu, Zhongzhu Hong, Lili Xie, Hongyu Bian, Zhigao Yi, Xiaofeng Chen, Yiming Wu, Xiaorong Song, Juan Li, Qiushui Chen, Huanghao Yang, Xiaogang Liu.
Fuzhou University, Fuzhou, China; National University of Singapore, Singapore, Singapore; The Hong Kong Polytechnic University, Hong Kong SAR, China; Joint School of National University of Singapore and Tianjin University, Tianjin University, Fuzhou, China; Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, China; National University of Singapore Suzhou Research Institute, Suzhou, China.
Current X-ray imaging technologies involving flat-panel detectors have difficulty in imaging three-dimensional objects because fabrication of large-area, flexible, silicon-based photodetectors on highly curved surfaces remains a challenge. Here we demonstrate ultralong-lived X-ray trapping for flat-panel-free, high-resolution, three-dimensional imaging using a series of solution-processable, lanthanide-doped nanoscintillators. Corroborated by quantum mechanical simulations of defect formation and electronic structures, our experimental characterizations reveal that slow hopping of trapped electrons due to radiation-triggered anionic migration in host lattices can induce more than 30 days of persistent radioluminescence. We further demonstrate X-ray luminescence extension imaging with resolution greater than 20 line pairs per millimetre and optical memory longer than 15 days. These findings provide insight into mechanisms underlying X-ray energy conversion through enduring electron trapping and offer a paradigm to motivate future research in wearable X-ray detectors for patient-centred radiography and mammography, imaging-guided therapeutics, high-energy physics and deep learning in radiology.
DOI: 10.1038/s41586-021-03251-6