Less energy causes more scatter and more absorbed radiation by the patient. Collimators address the vast majority of gamma camera attenuation potential problems, but Compton scatter artifacts can still occur. Attenuation artifacts can be inherent to gamma radiation due to the energy it has.
ARTIFACT MEANING IN CARDIOLOGY SOFTWARE
Artifacts can occur when using multipeak radionucleotides such as 67Ga, 201Tl, and 111In, causing resolution degradation, causing subtle errors even with software corrections. Multiple window spatial recognition is the accuracy of dual-isotope positioning with multiple photons of different energy using their normalized reference ranges.Resolution and linearity artifacts are principally affected by spatial distortion, but modern developments have given us automatic updating of linear correction maps with minimal human involvement for correction, even with PET/MRI using flood histograms.Uniformity artifacts can arise from faults in the photomultiplier tube, sodium iodide crystal, as well as other electronic and mechanical problems.These artifacts can be categorized into uniformity, resolution and linearity, multiple window spatial registration, collimators, the field of view, and computer-related. With digitized gamma cameras, the acquired image raw data may show artifacts clearly, but post-processing, the artifacts may become subtle or altered and difficult to recognize. In nuclear medicine, imaging artifacts can be broadly divided into instrumental, radiopharmaceutical, technical, patient, and treatment-related. The imaging interpreter must verify the nature of the artifacts and may require further clinical information or examination to determine the cause and correct it if needed. Artifacts may represent false positive, false negative, or obscure results. The reporting physician must know of and recognize an artifact to differentiate it from a true representation or variant. Artifacts in nuclear medicine are abnormalities observed that misrepresent a physiologic process or anatomical structure as pathological, and this does not include variants (either abnormal or normal).
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