Abstract: In view of the great success of integrated PET-CT scanners, there is an increasing interest in its "cousin"-SPECT-CT systems. SPECT-CT can fuse the function information by SPECT and the anatomy information by CT in the same macnine, which enhanced the diagnosis sensitivity and the specificity greatly. This article summarized SPECT-CT some characteristics and the current clinical applications in the endocrine tumor, sentinel node, bone metastasis and lymphoma, et al.