What is iterative reconstruction in SPECT? Iterative reconstruction is a mathematical method used in SPECT to reconstruct tomographic images by repeatedly refining an estimated activity distribution until it best matches the measured projection data. Unlike filtered back projection, which applies…
What is filtered back projection in SPECT? Filtered back projection (FBP) is a mathematical reconstruction method used in SPECT to convert multiple projection images into cross-sectional slices. It works by “back projecting” each projection across the image space and applying…
How is data acquired in SPECT? In SPECT imaging, data are acquired by rotating one or more gamma camera heads around the patient and recording projection images at multiple angular positions. Each projection represents the spatial distribution of detected gamma…
How does SPECT differ from planar imaging? SPECT differs from planar imaging in that it produces three-dimensional tomographic images, whereas planar imaging produces a two-dimensional projection image. In planar imaging, all detected photons are summed along each line through the…
What is SPECT imaging? SPECT (Single Photon Emission Computed Tomography) is a tomographic nuclear medicine imaging technique that produces three-dimensional images of radiotracer distribution within the body. Unlike planar imaging, which produces a two-dimensional projection image, SPECT acquires multiple projections…
What is intrinsic and extrinsic uniformity in gamma camera imaging? Energy windowing is the process of selecting only detected photons that fall within a specified energy range around the photopeak of a radionuclide. It is used to reject scattered photons…
What is intrinsic and extrinsic uniformity in gamma camera imaging? Intrinsic uniformity refers to the uniformity of detector response across the scintillation crystal when measured without a collimator. It assesses how evenly the gamma camera detector records events over its…
What is intrinsic and extrinsic spatial resolution in gamma camera imaging? Intrinsic spatial resolution refers to the resolving ability of the gamma camera detector system itself, measured without a collimator. It reflects the performance of the scintillation crystal, photomultiplier tubes,…
What is the resolution–sensitivity trade-off in gamma camera imaging? The resolution–sensitivity trade-off in gamma camera imaging refers to the fundamental relationship in which improving spatial resolution reduces sensitivity, and improving sensitivity reduces spatial resolution. This trade-off is primarily determined by…
What determines sensitivity in gamma camera imaging? Sensitivity in gamma camera imaging refers to the system’s ability to detect emitted photons from the patient. It is usually defined as the number of detected counts per unit of administered activity. Sensitivity…