Glossary Terms Flashcards
180-degree linear interpolation
Type of algorithm use for multi slice computed tomography image reconstruction in which data acquired from a shorter distance away from the reconstructed slice location are interpolated
360 degree linear interpolation
Type of algorithm to use for multi slice computed tomography image reconstruction in which two sets of projection #DATA acquired 360° apart are used to form an image as precise z-axis location
The amount of x-ray energy absorbed in a unit of mass
it is measured in grays (Gy)
Absorbed dose
The ability of an individual CT detector to absorb and measure the transmitted Xray intensity incident upon it primarily controlled by the characteristics and physical make up of the detector and material
Absorption efficiency
The type of multi scan computed tomography detector array configured with the thinnest detectors at the center surrounded by detectors of incrementally increasing widths along the Z-axis
Adaptive array
Cone beam correction algorithm utilize to overcome potential attenuation calculation errors from the divergent beam of multi scan computed tomography systems
Advanced single-slice rebinning algorithm (ASSR)
The tendency of scintillation type CT detector to continue to glow in response to x radiation after the exposure source has been terminated
Afterglow
Quantification of the volume and density of calcium within the coronary arteries as calculated during a CT coronary artery calcification examination the score is used to indicate a patient’s risk of suffering a cardiac event
Agatston score
Acronym for as low as reasonably achievable the cardinal principle of radiation dose reduction for all radiologic procedures including city
ALARA
Mathematical filter applied to raw data during CT image reconstruction to remove blurring artifact inherent to back projection may also be referred to as a kernel
Algorithm
A form of streak artifact caused by an insufficient number of views obtained during data acquisition
Aliasing
A component of the data acquisition system (DAS)responsible for converting the electronica signal emitted by the CT detectors into digital form
Analog to digital converter (ADC)
The storage a CT data in either hard film or soft digital form
Archival
A component of the CT computer system responsible for receiving Raw scan data performing all of the major processing of the CT image and returning the reconstructed image to the storage memory of the host computer
Array Processor (AP)
Period of peak arterial enhancement after the bolus IV administration of Iodinated contrast material
Arterial phase
What arterial phase occurs approximately 25 to 35 seconds after the initiation of contrast agent administration
Hepatic
A form of noise on the CT image resulting from errors during the measurement of transmitted radiation by the detectors
Artifact
A neurologic sign characterized by loss of muscular coordination
Ataxia
The reduction in intensity of a radiation beam as it passes through a substance
Attenuation
The value assigned to an object quantifying its ability to attenuate an x-ray beam
Attenuation coefficient
CT system software used to adjust the milliamperage (mA)throughout an acquisition to reduce patient radiation does to a minimum
Automatic tube current modulation ( ATCM)
CT system software used to adjust the tube voltage (Kvp) based upon the changing patient attenuation along the scan acquisition range to reduce patient radiation does to a minimum
Automatic tube voltage selection (ATVS)
The mathematical process of CT image reconstruction whereby ray sun data are projected back onto a matrix
Back-projection
The phenomenon whereby low energy photons are absorbed as the x-ray beam passes through an object resulting in an increase in the average photon energy of the beam
Beam hardening
