Reconstruction of 4-Layer DOI detector equipped C-shaped PEM via list-mode iterative algorithm

This C-shaped PEM unit currently under development is designed for the very early stage detection of very small lesions, such as breast cancers. This PEM unit´s scanner is equipped with 4-layer Depth of Interaction (DOI) detectors, each of which contains small scintillator crystals. The scanner is positioned closely around the breast, providing both high resolution and sensitivity. The open end of the detector unit allows the arm to be placed there and the C-shaped design of the scanner accommodates a variety of patient physiques, ensuring inclusion of the entire breast into the effective field of view (FOV). In this work, list-mode iterative algorithms can be utilized for image reconstruction using incomplete acquisition datasets, due to this scanner´s module gap and large number of LORs. To evaluate the effect of using DOI detectors on C-shaped PEM images, and the resulting effective FOV of this PEM, Monte- Carlo simulations of the acquisitions from this PEM scanner were used for image reconstruction via list-mode DRAMA algorithms. Results indicate that while non-DOI detector contrast near the detector gap deteriorates substantially, use of a DOI detector system preserves a high level of contrast.