超低剂量CT结合新型迭代重建技术的原理及其研究进展

The principle and research progress of ultra-low dose CT combined with new iterative reconstruction technique

随着低剂量CT(LDCT)常规应用于临床胸部检查并得到临床和放射科医生的一致认可,能进一步降低辐射剂量的超低剂量CT(ULDCT)成为新的研究热点。新型迭代重建技术按利用空间不同分为在投影数据空间和图像数据空间均进行迭代计算的迭代重建技术、仅在投影数据空间进行迭代计算的迭代重建技术及最新的自适应统计迭代重建-V(ASiR-V)技术。第一类迭代重建技术能在几分钟的后处理时间内提供满足诊断要求的具有一定噪声的图像;第二类迭代重建技术能提供更高分辨率及更低噪声的图像但后处理时间较长;而ASiR-V技术结合了前两者的优势,能在1 min内获得空间分辨率高、噪声低的图像。

With the routine application of low-dose CT(LDCT)in clinical chest examination,it has been unanimously approved by clinical and radiologists.Ultra-low dose CT(ULDCT)which can further reduce the radiation dose has become a new research hotspot.The new iterative reconstruction techniques can be divided into the iterative reconstruction techniques for iterative computation in both projected data space and image data space,the iterative reconstruction techniques for iterative computation only in projected data space and the latest adaptive statistical iterative reconstruction-V(ASiR-V)technique.The first type of iteration reconstruction technique can provide the image with certain noise satisfying the diagnostic requirements within a few minutes postprocessing time.The second type of iterative reconstruction technology can provide higher resolution and lower noise images but the post-processing time is longer.ASiR-V technology combines the advantages of the first two,and can obtain images with high spatial resolution and low noise within 1 minute.ULDCT combined with the new iterative reconstruction technology can provide images that can be diagnosed by radiologists under the premise of a large reduction in radiation dose.It is expected that ULDCT combined with iterative reconstruction technology can be applied to all parts of the body in the future.In addition,new iterative reconstruction techniques will be developed to obtain better image quality under lower radiation dose.