正电子发射断层成像（PET）是一种对活体的生理机能进行成像的核医学成像方式。为了全方位地刻画生物体内的生命活动，双示踪PET技术被提出。此技术往往采用交错/同时注射、单次扫描的方式来获得两种示踪剂的放射性浓度分布信息，目前主要被应用于肿瘤和神经系统相关疾病的诊断和治疗中。由于两种示踪剂产生的光子能量不可区分，故双示踪PET图像的重建成为重点研究的关键技术之一。从PET的成像原理、示踪剂和双示踪PET重建技术等多个方面进行介绍，并重点讨论各类重建技术的优势和不足。最后，对双示踪PET成像技术在多参数、多模态成像领域中的发展和应用进行展望。

Positron Emission Tomography (PET) is a nuclear medical imaging technique for functional in vivo imaging. In order to image in vivo physiological activities from different aspects, dual-tracer PET approach is further proposed. By injecting two different tracers simultaneously, the radioactive concentration distribution of two tracers can be acquired within one single scan. Nowadays, dual-tracer PET has been applied on the diagnosis and treatments of tumors and neurological diseases. Due to the indistinguishable photon energies emitted from two tracers, dual-tracer PET reconstruction becomes challengeable. PET imaging mechanism, tracers and dual-tracer PET reconstruction are introduced, and the pros and cons of those reconstruction methods are discussed as well. In the end, the possible applications of dual-tracer PET imaging on multi-parameter and multi-mode imaging are prospected.