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Several different views of the head are available, including axial, coronal, reformatted coronal, and reformatted sagittal images. However, coronal images require the person to hyperextend their neck, which must be avoided if any possibility of neck injury exists. [8] CT scans of the head increase the risk of brain cancer, especially for ...
Of the CT scans, six to eleven percent are done in children, [168] an increase of seven to eightfold from 1980. [167] Similar increases have been seen in Europe and Asia. [167] In Calgary, Canada, 12.1% of people who present to the emergency with an urgent complaint received a CT scan, most commonly either of the head or of the abdomen.
Fig.1: Basic principle of tomography: superposition free tomographic cross sections S 1 and S 2 compared with the (not tomographic) projected image P Median plane sagittal tomography of the head by magnetic resonance imaging. Tomography is imaging by sections or sectioning that uses any kind of penetrating wave.
A CT scan can be performed in under a second and produce rapid results for clinicians, with its ease of use leading to an increase in CT scans performed in the United States from 3 million in 1980 to 62 million in 2007. Clinicians oftentimes take multiple scans, with 30% of individuals undergoing at least 3 scans in one study of CT scan usage. [36]
In conventional CT machines, an X-ray tube and detector are physically rotated behind a circular shroud (see the image above right). An alternative, short lived design, known as electron beam tomography (EBT), used electromagnetic deflection of an electron beam within a very large conical X-ray tube and a stationary array of detectors to achieve very high temporal resolution, for imaging of ...
A dual detector head gamma camera combined with a CT scanner, which provides localization of functional SPECT data, is termed a SPECT-CT camera, and has shown utility in advancing the field of molecular imaging. In most other medical imaging modalities, energy is passed through the body and the reaction or result is read by detectors.
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This gives a total scan time of 15–20 minutes. Multi-headed gamma cameras can accelerate acquisition. For example, a dual-headed camera can be used with heads spaced 180 degrees apart, allowing two projections to be acquired simultaneously, with each head requiring 180 degrees of rotation. Triple-head cameras with 120-degree spacing are also ...