Physics, Techniques and ProceduresView
in
computed tomography (CT), a collection of parallel or divergent
rays which encompass a
scanned field of view and which can be grouped together for processing, for example with the reconstruction
convolution kernel. In a
translate-rotate CT scanner, a
projection or view consists of a set of
attenuation measurements made along parallel rays during a single translation of the
X-ray tube-detector assembly. In a
third generation CT scanner (rotate-rotate), a view consists of the set of attenuation measurements made from all detectors from a single
X-ray source position. In a
fourth generation CT scanner, (rotate-stationary) a view consists of all measurements made from a single detector as the
X-ray source moves past the patient. See also
projection.
Partly from the analogy to
CT, the term "view" is often used in
MR imaging to refer to one line of raw data. For example, one frequency encoded echo at one amplitude of the
phase-encoding gradient may be called a view.
In
X-ray projection radiography and
fluoroscopy, the term "view" can refer to a particular angular orientation of the source and detector with respect to the object, as in an LAO view.
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