<p>Positron emission tomography - computed tomography (PET/CT) is an advanced molecular imaging technique that is mainly used for the early detection and diagnosis of major heart diseases and tumors. To reduce imaging artifacts caused by the patient’s respiratory motion, the mainstream respiratory control method such as gating technique has been widely used. Based on the optical fiber pressure sensor, a real-time analysis software system of respiratory motion information has been developed in this study. A gate alignment algorithm for correlating respiratory motion in PET/CT scanning was investigated. In this study, a real-time extraction algorithm of smooth respiratory waveform and a fast temporal phase segmentation algorithm were proposed, reducing the computational complexity and guaranteeing low latency and high recognition accuracy, and then they were implemented in the lower computer by programming. The software and hardware integration of the respiratory acquisition system with the fiber-optic sensor-based mattress was realized, and the whole prototype product was developed for experimental studies. Compared with the existing traditional methods, the average detection latency of the method in this study is less than 150 ms (about 300 ms for existing methods), and the relative error of temporal phase segmentation is about 1% (about 5% for existing methods). This study offers significant potential for enhancing PET/CT imaging quality and efficiency, with future steps aimed at integrating the system into commercial platforms for clinical validation.</p>