Ultra-High Spatial Resolution Clinical Positron Emission Tomography (PET) Systems

Positron emission tomography (PET) is an imaging modality for non-invasive visualization and quantification of molecular pathways in human diseases, with applications spanning clinical practice and biomedical research. Recent advances in PET system technology target ultra-high spatial resolution (<2 mm) to enhance diagnostic precision for early-stage disease detection and longitudinal monitoring. A key strategy involves organ-specific, or loco-regional, scanner configurations that optimize photon detection efficiency (PDE) while balancing the trade-off between spatial resolution and image signal-to-noise ratio (SNR). This study reviews innovations driving the development of next-generation clinical PET systems, including the following: (1) novel geometries tailored for anatomical regions such as the head/neck and breast, (2) high-performance detector materials and readout electronics, and (3) advanced image reconstruction algorithms. This paper emphasizes progress toward achieving ≤2 mm isotropic spatial resolution in clinical PET systems, and in particular focuses on describing a 1 mm3 resolution system dedicated to head-and-neck or breast cancer imaging that was developed in our laboratory.