During the IR loop, what occurs after updating the image with raw data?

In the iterative reconstruction (IR) process, after updating the image with raw data, the next step is back projection. This process involves taking the updated image estimate and projecting it back onto the various angles from which the data was originally acquired. Essentially, back projection serves to reintroduce the updated information into the computational model, which allows for further refinement of the image.

By iteratively applying this back projection technique, the reconstruction algorithm enhances image quality by minimizing noise and improving resolution. Each cycle of back projection helps to clarify the image based on the newly integrated data, which is critical for achieving clinically acceptable imaging results.

Forward projection, while relevant in reconstruction algorithms, occurs before back projection in the sequence. It is used to simulate the data that would be collected from a given image. Image smoothing deals with reducing noise in an image after it has been generated, rather than being part of the iterative reconstruction steps. Final image generation typically refers to the completion of the entire reconstruction process, which follows the iterative steps that include back projection.