Abstract: A system for low-count quantitative single-photon emission computed tomography (LC-QSPECT) is provided. The system is programmed to a) store a computer tomography (CT) scan of a subject being examining including a plurality of defined volumes of interest (VOIs) of the subject being examined; b) model a system matrix based on the stored CT, wherein the model describes the probability that photons emitted from each of the defined VOIs are detected in different projection bins, wherein a plurality of projection bins are defined around the subject and the defined VOIs; c) adjust the model with analysis of stray-radiation noise around the subject; d) detect, by the one or more sensors, one or more photons being emitted by an alpha-particle-emitting isotope; and e) execute the adjusted model with the one or more detected photons as inputs to determine a source VOI of the detected photons.

Abstract: Among the various aspects of the present disclosure is the provision of compositions of isotope-ligand complexes, methods of use thereof, and methods of chelating isotopes. The present disclosure also provides for methods for modulating ion channel transportation of radiopharmaceuticals. For example, the inhibition of radiopharmaceutical transport comprises administering an ion channel transport modulating or inhibiting agent (e.g., a calcium channel inhibitor) in an amount effective to inhibit gastrointestinal uptake.

Abstract: Among the various aspects of the present disclosure is the provision of compositions of imaging agents and methods for use in imaging ACE2 expression profiles. The ACE2 expression profiles may be used for detecting, monitoring, and evaluating ACE2 associated diseases, disorders, and conditions.