CT Chapter Flashcards by Rylee Quade

What is CT

The process of creating a cross-sectional tomographic plane of any part of the body

How well did you know this?

Not at all

Perfectly

What is exit radiation measured by

Detector assembly

How well did you know this?

Not at all

Perfectly

how does CT have less scatter

Fan beam uses filters to shape beam and reduce scatter

How well did you know this?

Not at all

Perfectly

Who is credited with the invention of Ct

Godfrey hounsfield and Allen cormack

How well did you know this?

Not at all

Perfectly

Most scanners are what generation

3rd generation

How well did you know this?

Not at all

Perfectly

EBCT

Election beam computed tomography

How well did you know this?

Not at all

Perfectly

Ebct gives increased

temporal resolution

How well did you know this?

Not at all

Perfectly

EBCT is usually used for

Cardiac scans

How well did you know this?

Not at all

Perfectly

6th generation CT scanner

Dual - source CT scanner

How well did you know this?

Not at all

Perfectly

Raw dat

Measured X-ray transmission values

How well did you know this?

Not at all

Perfectly

Volume element

Voxel

How well did you know this?

Not at all

Perfectly

Field of view

Determines amount of data displayed on monitor

How well did you know this?

Not at all

Perfectly

Numbers are called CT numbers or

Hounsfield units

How well did you know this?

Not at all

Perfectly

Hounsfield units air and gas

1000

How well did you know this?

Not at all

Perfectly

Water has a hounsfield unit of

Zero

How well did you know this?

Not at all

Perfectly

DAS

Data acquisition system

How well did you know this?

Not at all

Perfectly

Devices within the gantry

X-ray tube, das, and detect array

How well did you know this?

Not at all

Perfectly

Gantry can be titled up to

30 degrees

How well did you know this?

Not at all

Perfectly

Opening of the gantry

Aperture

How well did you know this?

Not at all

Perfectly

Table is made of

Low density carbon fiber composite

How well did you know this?

Not at all

Perfectly

Movement of the tube is called

Indexing

How well did you know this?

Not at all

Perfectly

Narrow window =I

Fewer shades of gray 08 high contrast

How well did you know this?

Not at all

Perfectly

Wide window =

More shades of gray , longer scale contrast

How well did you know this?

Not at all

Perfectly

Window level

Sets the mid point of gray levels

How well did you know this?

Not at all

Perfectly

MPR

Multiplanar reconstruction

Ability to reconstruct axial images into coronal, Sagittal or oblique body planes without additional radiation to patient

Exam of choice for head trauma

Spatial resolution

Ability to see small structures that are near similar small structures

Contrast resolution

Ability to differentiate between small density differences

Streaking artifact is also called

Beam hardening artifact

Isotropic viewing

Viewing in all directions

VCT

Volume Ct

Smaller the beam pitch

Better the spatial resolution

Isocenter

The point in space where radiation beams interact when gantry is rotated

Dose reporting must be part of

The permanent record for each exam

Most common reporting method

Dose-length product Dose times length of exam

Units used for DLP

MGy/cm

Thinner the slice

The higher the dose

what award was given to Hounsfield and Cormack and in what year

Nobel prize in 1979

which generation CT machine is the tube very close to the patient, increasing the patient dose

4th

6th generation computer has

two sets of detectors

6th generation CT machine has increases

temporal resolution

which generation uses an electron beam

5th generation

what is the abbreviation for electron beam CT

EBCT

which generation is dual source

6th

resolution of something moving

temporal resolution

which generation scanners are classified at high speed CT scanners

5th generation

what beam type does a 5th generation have

fan beam

what does dual energy source mean and what is the abbreviation

it has two x-ray beams, DSCT

voxel volume

the product of the pixel area and slice thickness

what determines the amount of data displayed on the monitor

field of view

CT numbers are also called

Hounsfield units

DAS

detector array system

slip ring technology

low voltage electrical contacts within the gantry are designed to allow continuous rotation of an x-ray tube without the use of cables connecting internal and external components

another work for voxel

volume unit

gantry can be tilted how many degrees

opening in the center of the gantry is called

apature

CT table is made of

carbon fiber

window width determines the number of

gray levels to be displayed in the image

narrow window width results in

fewer shades of grey, so higher contrast

window level determines the

midpoint of the range of grey levels to be displayed on the monitor

what should the window level be set to

The CT number of the tissue of interest

what should the window width be set with

a range of values that would optimize the contrast between the tissues in the image

would a high-resolution CT scan protocol use thin-slice or thick-thickness protocols

higher resolution used thinner slice

thinner slices increase/decrease pt dose

increase pt dose because of the increase in mAs

Multiplanar reconstruction (MPR)

sectional image can be generated in any desired plane by selecting a particular plane of data

Helical CT, single slice Helical CT

slip ring technology allows 360 degree continuous rotation of tube and detector, reduces scan times to sub-second per slice

what does VCT stand for

volume CT

VCT

multislice scanners with 64 detector rows or more, must be a cone configuation

CTA

computed tomography angiography

What is CTA

an application of spiral CT that uses three dimensional imaging techniques

Advantages to CTA over conventional angiography

images can be reconstructed without additional radiation exposure, overlying structures can be eliminated, does not require arterial puncture

CT Chapter Flashcards

(72 cards)