unit 1 reading

spatial resolution

ability of the system to define small objects

low contrast resolution

ability of the system to differentiate objects of similar densities

temporal resolution

speed at which data can be acquired

what are the 3 elements for helical scanning?

1. constant xray output

2. constant table movement

3. constant xray tube rotation

helicla scanning is sometimes referred to as…

volumetric scanning

the newer 256 and 320 detector systems with detector widths of …

0.625 and .5 mm

describe it: describe adaptive, nonuniform array, hybrid array

variable thinner rows centrally and wider rows peripherally

MDCT provides longer and faster x coverage per gantry rotation

z-axis

MDCT systems have increased the x of the gantry, which further increases x per unit time

speed / volume coverage

binning

the action of combining slices in various combinations

what is the advantage of the dual CT

it halved the temporal resolution (data acquisition time) because each xray tube and detector array configuration only needs to rotate half of the angle

MDCT designs caused what downfall

fourth generation systems of complete ring. it would be too expensive because of the amount of detectors needed to perform how a MDCT would

what is the dual CT scanner called produced by siemens

Somatom Definition CT Scanner

what is the primary goal of the dual scanner

increase scan speed — to have the least amount of motion artifacts, specifically involuntary movement

what is unique about the fourth generation conventional CT

400 degree rotation

axial scans are typically used in protocols in which acquisition is not a major concern and x such as internal auditory canal

optimal resolution is required