# CT Physics 2 Hhh

51 Questions | Total Attempts: 415  Settings  Ct resistry review physichs

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• 1.
Filment sizes for modern CT x-ray tubes range between
• A.

0.5 and 1.2 mm

• B.

2.0 and 3.0 mm

• C.

5.5 and 7.8 mm

• D.

25.0 and31.5 mm

• 2.
The mathematical process that allows MDCT images to be reconstructed at any point along the acquired volume is commonly referred to ass
• A.

Iteration

• B.

Filtered back-projection

• C.

Fourier reconstruction

• D.

Z-filtering

• 3.
During ct x-ray exposure, the product of the seleted mA setting and the scan time is called
• A.

Effective mAs

• B.

Peak mAs

• C.

Absorbed mAs

• D.

Constant mAs

• 4.
The matematical manipulations required during the reconstruction of a ct image are accomplished using a (n)
• A.

Algorithm

• B.

Kerenel

• C.

Mathematical filter function

• D.

1 and 2

• E.

1,2 and 3

• 5.
The electronic combination of signals from adjacent detectors to form a CT image is called
• A.

Binning

• B.

Interpolaation

• C.

Z-filtering

• D.

Partial volume averaging

• 6.
The streaking artifact that occurs in the area of the posterior fossa during a CT examination of the brain may be referred to as
• A.

Cupping

• B.

Boiled egg

• C.

Stairstep

• D.

The Hounsfield bar

• 7.
Which of the following 3D imaging techniques is utilized to provide "fly-through" images during CT colonography
• A.

Orthographic volume rendering

• B.

• C.

Perspective volume rendering

• D.

Minimum intensity projection (min-IP)

• 8.
An MDCT image is reconstructed using a 512 matrix and aDFOV of 38 cm. if the detector collimation is set to a section width of 1.25 mm, what is the volume of each voxel?
• A.

0.69mm

• B.

0.93mm

• C.

1.26 mm

• D.

1.68mm

• 9.
Which of the following sttements about collimation of the CT x-ray beam is false?
• A.

Collimation of the x-ray beam occurs both before and after the patients

• B.

Collimation of the beam occurs in the z-axis, thus affecting slice thickness

• C.

Increases in collimation increase the intensity of the primary beam

• D.

Collimation of the ct x-ray beam is used to limit the detection of scatter radiation

• 10.
The major disadvantage of the back-projection method of image reconstruction is the appearance of the
• A.

Partial volume effect

• B.

Ring artifact

• C.

Gibb phenomenon

• D.

Star artifact

• 11.
• A.

Euler constant

• B.

Incident intensity

• C.

Absorber thickness

• D.

Transmitted intensity

• 12.
A high-resolution comb is utilized by an MSCT detector array in an effort to reduce:
• A.

• B.

• C.

Low spatial frequency signal

• D.

High spatial frequency signal

• 13.
When choosing a scan field of view, the CT technologist is controlling the
• A.

Diameter of data acquistion

• B.

Number activated detectors within the array

• C.

Correction factors for the specific area of anatomic interest

• D.

1and 2

• E.

1,2,3

• 14.
The geometric efficiency of a CT detector is influenced primarily by the
• A.

Atomic number of the detector material

• B.

Size of the detector element

• C.

Size of the tube filament

• D.

Amount of interspace material between detectors

• 15.
Which of the following factors may affect the attenuation of an object during CT data acquisition?
• A.

Beam pitch

• B.

MA

• C.

KVp

• D.

Algorithm

• 16.
An image that is reconstructed a second time with some change in technical factor is said to be
• A.

Reiterated

• B.

Post-processed

• C.

Retrospective

• D.

Reformatted

• 17.
The FDK algorithm may be applied to MSCT acquisition data to overcome image artifacts from
• A.

Patient motion

• B.

Beam hardening

• C.

Paartial volume averaging

• D.

Beam divergence

• 18.
The polyenergetic x-ray beam emitted from a cT x-ray tube is susceptible to artifacts due to the phenomenon known as
• A.

Beam hardening

• B.

Density bloom

• C.

Kerma

• D.

Partial volume

• 19.
Daily air or water calibration performed to evaluate which of the following components of image quality
• A.

Contrast resolution

• B.

Temporal resolution

• C.

Uniformity

• D.

Linearity

• 20.
The limiting resolution is determined (MTF) at a pint where the signal frequency corresponding to a particular object has reached
• A.

10%

• B.

20%

• C.

50%

• D.

100%

• 21.
Which of the following is not a part of the ct tube?
• A.

Tungsten target

• B.

Collimator

• C.

Rotating anode

• D.

Filiament

• 22.
X-rays are produced whenever fas-moving electrons collide with any form of matter because
• A.

The electron splits into two-x-ray photons of equal enery up in impact with the matter

• B.

The electron loses kinetic enery which is converted into the emission of an x-ray photon

• C.

The electron converts the electron it collides with in to an xprayphoton

• D.

1 and 2

• E.

2 only

• 23.
Which of th following is FALSE regarding CT systmes
• A.

They are limited to non-oblique transverse scanning

• B.

They cannot generate a straight coronal or sagittal image

• C.

They have no moving parts

• D.

1 and3

• E.

1 2 3

• 24.
Which of the following statements is FALSE regarding 3D SSD
• A.

Helical image data is well suited for 3d ssd because there is minimal misregistration or gaps

• B.

The volume data, from which the 3d ssd is generated, is created by combining transverse, sagittal, and coronal reconstructions

• C.

The tissue surface may be selected by using a threshold value equal to the tissue's ct number

• D.

Patient motion during the scan is detrimental to the quality of th 3d images

• 25.
In which technique are tissues other than the surface of a structure excluded by setting a treshold value and eliminating pixels above or below that threshold
• A.

Volume rendering

• B.

Multi-planar reconstruction

• C.

Maximum intensity projection

• D.