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: A system for single-photon emission computed tomography (SPECT) is provided. The system includes a computer device comprises at least one processor in communication with at least one memory device. The at least one processor is programmed to: a) store a model trained to generate an attenuation map of a subject being examined; b) receive a scatter-energy window projection of a first subject to be examined; c) execute the model with the scatter-energy window projection of the first subject as an input, wherein the model generates an attenuation map; d) receive a photopeak-energy window projection of the first subject to be examined; and e) perform attenuation compensation on the photopeak-energy window projection using the generated attenuation map.

Abstract: A system for single-photon emission computed tomography (SPECT) is provided. The system includes a computer device comprises at least one processor in communication with at least one memory device. The at least one processor is programmed to: a) store a model trained to denoise computer tomography (CT) scans of a subject being examined; b) receive a CT scan of a first subject being examined; c) execute the model with the CT scan of the first subject as an input, wherein the model performs denoising on the CT scan while accounting for an observer loss function; and d) output a denoised-CT scan of the first subject.

Abstract: Among the various aspects of the present disclosure is the provision of methods for estimation-based segmentation of nuclear medicine images, as well as methods of transmission-less attenuation and scatter compensation of nuclear medicine images.