Spect CT is an imaging technique which allows acquiring two different types of images separately or concomitantly in a single body scan. Concomitant use of images provides detailed information regarding functions of body parts and organs.Sentinel lymph node mapping is especially used to investigate lymph node involvement in breast cancer, malignant melanoma, head and neck tumors, early stage cervical cancer and urinary bladder tumor.Considering diseases of the skeletal system, it helps detection of metastases in malignant diseases and differentiation of metastasis and degenerative changes. Moreover, it is useful to identify parathyroid adenoma among parathyroid diseases and image perfusion of heart.