What can be expected with higher subsets and iterations in OSEM reconstruction?

In Ordered Subset Expectation Maximization (OSEM) reconstruction, higher subsets and iterations are associated with improvements in image quality, specifically in terms of resolution and detail. This method is widely used in PET imaging because it helps to optimize the process of image reconstruction.

When the number of subsets is increased, the algorithm processes smaller groups of projection data at once. This allows for more frequent updates to the image estimate during each iteration, which can lead to finer resolution. Additionally, increasing the number of iterations allows for a more thorough refinement of the image, enhancing the detail captured in the final reconstructed images.

The interaction of these factors leads to sharper images with more defined edges and better visualization of small structures within the scanned area. Therefore, higher subsets and iterations effectively enhance the quality of the reconstructed images in PET scans, making the selected answer a reflection of the underlying principles of this reconstruction technique.