What is recovery coefficient in PET? The recovery coefficient (RC) in PET is a measure of how accurately the measured activity concentration in a structure reflects its true activity concentration. It quantifies the impact of partial volume effects on small…
What determines spatial resolution in SPECT and PET? Spatial resolution in SPECT and PET is determined by different dominant physical factors. In SPECT, spatial resolution is primarily limited by collimator geometry and source-to-detector distance. In PET, spatial resolution is limited…
What is the partial volume effect in SPECT and PET? The partial volume effect is the underestimation of true tracer uptake in small structures due to limited spatial resolution. When a structure is smaller than approximately two to three times…
What determines contrast resolution in SPECT and PET? Contrast resolution in SPECT and PET is determined primarily by count statistics, noise, scatter, attenuation effects, and reconstruction parameters. It reflects the ability to detect differences in tracer uptake between adjacent regions.…
What is spatial resolution versus contrast resolution in radionuclide imaging? Spatial resolution refers to the ability of an imaging system to distinguish two closely spaced structures as separate. It describes how sharply edges and small objects are represented. Contrast resolution…
What determines image quality in radionuclide imaging? Image quality in radionuclide imaging is determined by a combination of count statistics, spatial resolution, contrast resolution, and physical correction modelling (including attenuation and scatter correction). Unlike CT or MRI, image quality in…
What is PET reconstruction? PET reconstruction is the mathematical process of converting millions of detected coincidence events into cross-sectional images representing the three-dimensional distribution of radiotracer activity. Each coincidence event defines a line of response along which the annihilation occurred.…
What is attenuation correction in PET? Attenuation correction in PET compensates for the loss of annihilation photons as they pass through the body before reaching the detectors. Without correction, deeper structures appear falsely less active because fewer photons are detected.…
What limits spatial resolution in PET? Spatial resolution in PET is fundamentally limited by three physical factors: positron range, non-collinearity of annihilation photons, and detector size. Even with perfect reconstruction, these factors introduce unavoidable uncertainty in localising the annihilation event.…
What determines spatial resolution in PET? Spatial resolution in PET is determined by a combination of detector resolution, positron range, and non-collinearity of annihilation photons. Unlike SPECT, PET resolution is not limited by mechanical collimation but by fundamental physical processes…
