Helical cone beam computed tomography
Encyclopedia
Spiral computed tomography is a computed tomography
, technology involving movement in a spiral pattern for the purpose of increasing resolution. Most modern hospitals currently use spiral CT scanners.
CT beam types have included parallel beams, fan-beams, and cone-beams.
, who is credited with the invention prefers the term Spiral scan CT, arguing that spiral is synonym
ous with helical: for example as used in 'spiral staircase'.
Since its invention by Kalender in the 1980s, helical scan CT machines have steadily increased the number of rows of detectors (slices) they deploy. The prototype
16 multi-slice scanner was introduced in 2001 and in 2004, 64 multislice scanners are on the market. These can produce an image in less than a second and thus can obtain images of the heart and its blood
vessels (coronary vessels) as if frozen in time.
The earliest devices, developed in 1989, were called "SSCT", for "single-slice spiral computed tomography". In 1998, "MSCT" or "multi-slice spiral computed tomography" was introduced.
Helical (or spiral) cone beam computed tomography (commonly abbreviated CBCT) is a type of three dimensional computed tomography
(CT) in which the source (usually of x-ray
s) describes a helical
trajectory relative to the object while a two dimensional array of detectors measures the transmitted radiation on part of a cone of rays emanating from the source.
In practical helical cone beam x-ray CT machines, the source and array of detectors are mounted on a rotating gantry while the patient is moved axially at a uniform rate. Earlier x-ray CT scanners imaged one slice at a time by rotating source and one dimensional array of detectors while the patient remained static. The helical scan method reduces the x-ray dose to the patient required for a given resolution while scanning more quickly. This is however at the cost of greater mathematical complexity in the reconstruction of the image
from the measurements.
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
, technology involving movement in a spiral pattern for the purpose of increasing resolution. Most modern hospitals currently use spiral CT scanners.
CT beam types have included parallel beams, fan-beams, and cone-beams.
SSCT and MSCT
Willi KalenderWilli Kalender
Willi A. Kalender is a medical physicist credited with the invention and development of spiral scan computed tomography.He received his Master's Degree and Ph.D...
, who is credited with the invention prefers the term Spiral scan CT, arguing that spiral is synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
ous with helical: for example as used in 'spiral staircase'.
Since its invention by Kalender in the 1980s, helical scan CT machines have steadily increased the number of rows of detectors (slices) they deploy. The prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
16 multi-slice scanner was introduced in 2001 and in 2004, 64 multislice scanners are on the market. These can produce an image in less than a second and thus can obtain images of the heart and its blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
vessels (coronary vessels) as if frozen in time.
The earliest devices, developed in 1989, were called "SSCT", for "single-slice spiral computed tomography". In 1998, "MSCT" or "multi-slice spiral computed tomography" was introduced.
Helical (or spiral) cone beam computed tomography
In spiral cone-beam computed tomography, the beam is in the shape of a beam or a cone.Helical (or spiral) cone beam computed tomography (commonly abbreviated CBCT) is a type of three dimensional computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
(CT) in which the source (usually of x-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
s) describes a helical
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
trajectory relative to the object while a two dimensional array of detectors measures the transmitted radiation on part of a cone of rays emanating from the source.
In practical helical cone beam x-ray CT machines, the source and array of detectors are mounted on a rotating gantry while the patient is moved axially at a uniform rate. Earlier x-ray CT scanners imaged one slice at a time by rotating source and one dimensional array of detectors while the patient remained static. The helical scan method reduces the x-ray dose to the patient required for a given resolution while scanning more quickly. This is however at the cost of greater mathematical complexity in the reconstruction of the image
Image editing
Image editing encompasses the processes of altering images, whether they be digital photographs, traditional analog photographs, or illustrations. Traditional analog image editing is known as photo retouching, using tools such as an airbrush to modify photographs, or editing illustrations with any...
from the measurements.