Zhang Haowei, Li Shuhan, Liu Ying, Lu Heqing
School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China.
Department of Equipment, Shanghai First Maternity and Infant Hospital, Shanghai 201204, P. R. China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2023 Oct 25;40(5):1012-1018. doi: 10.7507/1001-5515.202305015.
In recent years, photon-counting computed tomography (PCD-CT) based on photon-counting detectors (PCDs) has become increasingly utilized in clinical practice. Compared with conventional CT, PCD-CT has the potential to achieve micron-level spatial resolution, lower radiation dose, negligible electronic noise, multi-energy imaging, and material identification, etc. This advancement facilitates the promotion of ultra-low dose scans in clinical scenarios, potentially detecting minimal and hidden lesions, thus significantly improving image quality. However, the current state of the art is limited and issues such as charge sharing, pulse pileup, K-escape and count rate drift remain unresolved. These issues could lead to a decrease in image resolution and energy resolution, while an increasing in image noise and ring artifact and so on. This article systematically reviewed the physical principles of PCD-CT, and outlined the structural differences between PCDs and energy integration detectors (EIDs), and the current challenges in the development of PCD-CT. In addition, the advantages and disadvantages of three detector materials were analysed. Then, the clinical benefits of PCD-CT were presented through the clinical application of PCD-CT in the three diseases with the highest mortality rate in China (cardiovascular disease, tumour and respiratory disease). The overall aim of the article is to comprehensively assist medical professionals in understanding the technological innovations and current technical limitations of PCD-CT, while highlighting the urgent problems that PCD-CT needs to address in the coming years.
近年来，基于光子计数探测器（PCD）的光子计数计算机断层扫描（PCD-CT）在临床实践中的应用越来越广泛。与传统CT相比，PCD-CT有潜力实现微米级的空间分辨率、更低的辐射剂量、可忽略不计的电子噪声、多能量成像以及物质识别等。这一进展有助于在临床场景中推广超低剂量扫描，有可能检测到微小和隐匿性病变，从而显著提高图像质量。然而，目前的技术水平有限，电荷共享、脉冲堆积、K逃逸和计数率漂移等问题仍未得到解决。这些问题可能导致图像分辨率和能量分辨率下降，同时图像噪声和环形伪影增加等。本文系统地回顾了PCD-CT的物理原理，概述了PCD与能量积分探测器（EID）之间的结构差异以及PCD-CT发展中目前面临的挑战。此外，分析了三种探测器材料的优缺点。然后，通过PCD-CT在中国死亡率最高的三种疾病（心血管疾病、肿瘤和呼吸系统疾病）中的临床应用，展示了PCD-CT的临床益处。本文的总体目的是全面帮助医学专业人员了解PCD-CT的技术创新和当前技术局限性，同时突出PCD-CT在未来几年需要解决的紧迫问题。
