Projected surface methods are a diverse set of techniques used in medical imaging to create cross-sectional images of a patient’s body. These methods collect data from various angles and project it onto a virtual surface to reconstruct the internal structure. Different imaging modalities like CT, MRI, PET, and SPECT employ projected surface methods, each with unique principles, strengths, and limitations. The image reconstruction process involves applying algorithms like FBP, SIRT, ART, and statistical iterative techniques to transform raw data into clinically useful images.