Electron tomography involves the collection of a tilt series of electron microscopy images, typically using a Transmission Electron Microscope (TEM). The sample is tilted incrementally, and images are taken at each angle, usually within a range of ±60 to ±70 degrees. These images are then computationally reconstructed into a 3D model using algorithms such as weighted back-projection or iterative reconstruction techniques. This 3D model provides a detailed view of the sample's internal structure.