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This makes CT scan the most appropriate term, which is used by radiologists in common vernacular as well as in textbooks and scientific papers. [218] [219] [220] In Medical Subject Headings (MeSH), computed axial tomography was used from 1977 to 1979, but the current indexing explicitly includes X-ray in the title. [221]
However, essential mathematics and reconstruction algorithms used for CT and OPT are similar; for example, radon transform or iterative reconstruction based on projection data are used in both medical CT scan and OPT for 3D reconstruction. Both medical CT and OPT compute 3D volumes based on transmission of the photon through the material of ...
Low-dose high-resolution (1.25 mm) chest CT. HRCT is performed using a conventional CT scanner. However, imaging parameters are chosen so as to maximize spatial resolution: [1] a narrow slice width is used (usually 1–2 mm), a high spatial resolution image reconstruction algorithm is used, field of view is minimized, so as to minimize the size of each pixel, and other scan factors (e.g. focal ...
Electron beam CT scanners are considered a fifth generation CT scanner, with first generation being the pencil beam with translation and rotation, second generation being a fan beam with similar motion to its predecessor, third generation having both rotating fan beam and detectors and fourth generation being a fan beam with a rotating movement but fixed detector.
Quantitative CT scans are primarily used to evaluate bone mineral density at the lumbar spine and hip. In general, solid phantoms placed in a pad under the patient during CT image acquisition are used for calibration. These phantoms contain materials that represent a number of different equivalent bone mineral densities.
An imaging phantom for determining CT performance Imaging phantom as seen on a medical ultrasound machine. Imaging phantom, or simply phantom, is a specially designed object that is scanned or imaged in the field of medical imaging to evaluate, analyze, and tune the performance of various imaging devices. [1]
In order to obtain spatial information about the gamma-ray emissions from an imaging subject (e.g. a person's heart muscle cells which have absorbed an intravenous injected radioactive, usually thallium-201 or technetium-99m, medicinal imaging agent) a method of correlating the detected photons with their point of origin is required.
Such scans are most useful for tissues outside the brain, where location of tissues may be far more variable. For example, SPECT/CT may be used in sestamibi parathyroid scan applications, where the technique is useful in locating ectopic parathyroid adenomas which may not be in their usual locations in the thyroid gland. [14]