MED
In the literature: open
Imaging without tomographic reconstruction
In plain words
If the timing becomes precise enough, each detected pair marks its own point in space, so the image can be built without reconstruction. The timing and sampling requirements for that are not worked out.
Precise statement
Establish the coincidence time resolution, detector solid-angle coverage and count statistics at which direct event-by-event image formation matches or beats iterative tomographic reconstruction in task-based detectability for lesions of 5 to 10 mm. An answer is the threshold condition, stated in ps and counts, with the comparison metric.
What would settle it
Simulation and phantom studies comparing direct and reconstructed images across timing resolution at fixed counts.