physics of pet and spect imaging pdf vamg

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==> physics of pet and spect imaging pdf <==

The physics of PET (Positron Emission Tomography) and SPECT (Single Photon Emission Computed Tomography) imaging revolves around the principles of nuclear medicine and the detection of gamma radiation. PET imaging utilizes radiotracers that emit positrons, which annihilate with electrons, producing two 511 keV gamma photons traveling in opposite directions. Detectors in the PET scanner capture these photons to reconstruct a three-dimensional image of metabolic activity in the body, highlighting areas with increased radiotracer uptake, commonly used in oncology, cardiology, and neurology. Conversely, SPECT employs gamma-emitting isotopes that are injected into the body, where they emit single photons as they decay. SPECT cameras, equipped with collimators and detectors, capture these emissions to create detailed images of physiological functions, such as blood flow and regional organ activity. Both modalities rely on advanced algorithms for image reconstruction and require careful consideration of factors such as attenuation correction, spatial resolution, and timing of photon detection. Ultimately, the choice between PET and SPECT often depends on the specific clinical context, the type of information needed, and the availability of radiotracers. Together, these imaging techniques provide invaluable insights into various diseases and help guide diagnosis and treatment planning.