Abstract: 〗［Abstract］ Objective〖HTSS〗〓To investigate the effects of the sequential lumbar intervertebral disc scanning mode and the continuous lumbar interverbral disc reconstruction mode on computed tomography(CT) radiation dose and image quality of lumbar intervertebral disc.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓One hundred and twentyeight patients with clinically suspected lumbar  disc herniation were randomly divided into two groups. One group(group A) used conventional sequential lumbar intervertebral disc scanning mode; another group(group B) used the scan mode with the automatic expose control system that the normal intervertebral disc was reconstructed by continuous lumbar scanning, in which the original data were reconstructed by multiplane reconstruction after scanning. The reconstructed axial images were corresponding to the part of the conventional disc position. Then the radiation doses of the two mode scans were recorded and the image quality of the corresponding axial images was analyzed through the doubleblind method by two qualified diagnostic doctors.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓The scan time and radiation dose of group B in lumbar disc reconstruction mode was less than those of group A in sequential lumbar disc scan mode(P＜005). The signaltonoise ratio of abdominal aorta in group B was lower than that in group A(P＜005). However, two diagnostic doctors had consistent subjective rating for image quality. Two groups can better display lumber diseases, especially the lumbar vertebral reconstruction model(group B) is more convenient for stereoscopic observation.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓For the CT examination of lumbar intervertebral disc, the continuous lumbar interverbral disc reconstruction mode combined with automatic expose control technique can reduce the radiation dose.

Key words: lumber interverbral disc, tomography, spiral computed, radiation dosage