Development of a motion correction system for respiratory-gated PET study

A respiratory motion during whole-body imaging has been recognized as a source of image quality degradation and reduces the quantitative accuracy of positron emission tomography (PET) study. The aim of this study is to evaluate respiratory gating system and to develop a respiratory motion correction system using trigger generating device built in-house and gated-PET data acquisition mode. We utilized a commercially available laser optical sensor to detect respiratory motion during PET scanning. Each respiratory cycle is divided into 4 bins defined from average peak interval and irregular peak within the breathing motion. The acquired data within the time bins correspond to different positions within the breathing cycle and stored for the post motion correction. Motion data of diaphragm and chest wall was calculated by CT image acquisition during the normal inspiration and expiration position. In the images of a phantom, the blurring artifact due to breathing motion was reduced by our correction method. This technique improves the quantitative specific activity of the tracer which is distorted because of the respiratory motion.