A SPECT scanner, or Single Photon Emission Computed Tomography scanner, is a medical imaging device that helps doctors visualize blood flow and activity in various organs. It works by using a small amount of radioactive material, which emits gamma rays. These rays are detected by the scanner to create detailed images of the body's internal structures. SPECT scans are commonly used to assess conditions related to the heart, brain, and bones. They can help diagnose diseases such as coronary artery disease and Alzheimer's disease, as well as evaluate the effectiveness of treatments.