Question 1

A series of tissue density values that evolved for CT measurements is called ____ units.

Accepted Answer

A)  Hounsfield
B)  H & D
C)  attenuation
D)  iterativeE) None of the above
F) All of the above A

Question 2

The range of CT numbers or Hounsfield Units varies from

Accepted Answer

A)  100 to 300.
B)  -100 to +300.
C)  -1000 to +3000.
D)  1000 to +3000.E) B) and C)
F) A) and B)

Question 3

CT image data is acquired in the

Accepted Answer

A)  coronal plane and reconstructed in the axial plane .
B)  transverse plane and reconstructed in any plane.
C)  sagittal plane .
D)  axial plane and reconstructed in the coronal plane.E) C) and D)
F) B) and D)

Question 4

MSCT scanners have evolved greatly over the last few years, particularly with regard to slice combinations, scanning speed, and clinical utility.As these scanners gather more slices of data per rotation, a major technological challenge is

Accepted Answer

A)   the amount of data handled by the computer.
B)   the number of images to be analyzed by the clinician.
C)   developing technologies to minimize dose.
D)   all of the aboveE) C) and D)
F) B) and C)

Question 5

The CT radiation beam is collimated

Accepted Answer

A)  at the tube exit.
B)  at the detector entrance.
C)  pre-patient and post-patient.
D)  all of the aboveE) A) and B)
F) B) and D)

Question 6

If the table is moving at 5 mm/sec., and a pitch of 0.8 is being used, what is the section thickness?

Accepted Answer

The answer of If the table is moving at 5...

Question 7

The gantry of the CT unit contains the

Accepted Answer

A)  post-processing workstation.
B)  operator's interface.
C)  x-ray tube.
D)  all of the aboveE) C) and D)
F) A) and D) C

Question 8

The CT console provides the radiographer access to

Accepted Answer

A)  the software program.
B)  data acquisition.
C)  data display.
D)  all of the aboveE) A) and B)
F) B) and D)

Question 9

Contemporary CT scanners use solid state detectors.These detectors utilize

Accepted Answer

A)  sodium iodide crystals.
B)  rare earth ceramic scintillators.
C)  xenon gas.
D)  freon gas.E) C) and D)
F) A) and B)

Question 10

A ____ artifact is caused by the presence of metal in the patient.

Accepted Answer

A)  beam-hardening
B)  ring
C)  star
D)  streakE) A) and C)
F) A) and D)

Question 11

With MSCT scanners, resolution is primarily determined by

Accepted Answer

A)   prepatient collimation.
B)   dose.
C)   collimation at the detector.
D)   gantry rotation speed.E) A) and D)
F) A) and B)

Question 12

The CTDI dose measurement

Accepted Answer

A)  is slice-based.
B)  takes into account the total amount of irradiated tissue.
C)  represents the average total dose to the patient during the examination.
D)  measures entrance skin exposure (ES
E)  .E) B) and D)
F) B) and C)

Question 13

The ____ is determined by how well the detector converts the absorbed photon information to a digital signal for the computer.

Accepted Answer

A)  capture efficiency
B)  absorption efficiency
C)  conversion efficiency
D)  response timeE) A) and B)
F) A) and C)

Question 14

If the table is moving at 12 mm/sec., and a section thickness of 10 mm is being acquired, what is the pitch?

Accepted Answer

The answer of If the table is moving at 12...

Question 15

A ____ artifact is caused by attenuation of the beam as it passes through the patient.

Accepted Answer

A)  beam-hardening
B)  ring
C)  star
D)  streakE) B) and C)
F) C) and D)

Question 16

The ____ is how well the detectors receive photons from the patient.

Accepted Answer

A)  capture efficiency
B)  absorption efficiency
C)  conversion efficiency
D)  response timeE) None of the above
F) A) and C)

Question 17

The CT table is

Accepted Answer

A)  made of carbon graphite.
B)  rated for maximum weight.
C)  motor-driven.
D)  all of the aboveE) A) and B)
F) A) and C)

Question 18

In order for a CT x-ray photon to be measured, it must
1) enter the detector
2) be absorbed by the detector material
3) transmit through the detector to be back-projected
4) have sufficient energy to undergo a Compton interaction
5) be converted to light and then electrical energy as a signal

Accepted Answer

A)  1, 3, 4, and 5
B)  1, 2, and 5
C)  1, 2, and 4
D)  1, 4, and 5E) A) and B)
F) All of the above B

Question 19

Modern pulsed CT scanners operate at

Accepted Answer

A)  120 kVp.
B)  1 to 5 msec. pulses.
C)  up to 1,000 mA.
D)  all of the aboveE) A) and D)
F) B) and D)

Question 20

The most recent generation of CT scanners use a ____ motion.

Accepted Answer

A)  translate-rotate
B)  helical
C)  linear
D)  ellipticalE) A) and B)
F) B) and C)

Exam 41: Computed Tomography

A series of tissue density values that evolved for CT measurements is called ____ units.

Correct AnswerverifiedA

The range of CT numbers or Hounsfield Units varies from

Correct AnswerverifiedShow Answer

CT image data is acquired in the

Correct AnswerverifiedShow Answer

MSCT scanners have evolved greatly over the last few years, particularly with regard to slice combinations, scanning speed, and clinical utility.As these scanners gather more slices of data per rotation, a major technological challenge is

Correct AnswerverifiedShow Answer

The CT radiation beam is collimated

Correct AnswerverifiedShow Answer

If the table is moving at 5 mm/sec., and a pitch of 0.8 is being used, what is the section thickness?

Correct AnswerverifiedShow Answer

The gantry of the CT unit contains the

Correct AnswerverifiedC

The CT console provides the radiographer access to

Correct AnswerverifiedShow Answer

Contemporary CT scanners use solid state detectors.These detectors utilize

Correct AnswerverifiedShow Answer

A ____ artifact is caused by the presence of metal in the patient.

Correct AnswerverifiedShow Answer

With MSCT scanners, resolution is primarily determined by

Correct AnswerverifiedShow Answer

The CTDI dose measurement

Correct AnswerverifiedShow Answer

The ____ is determined by how well the detector converts the absorbed photon information to a digital signal for the computer.

Correct AnswerverifiedShow Answer

If the table is moving at 12 mm/sec., and a section thickness of 10 mm is being acquired, what is the pitch?

Correct AnswerverifiedShow Answer

A ____ artifact is caused by attenuation of the beam as it passes through the patient.

Correct AnswerverifiedShow Answer

The ____ is how well the detectors receive photons from the patient.

Correct AnswerverifiedShow Answer

The CT table is

Correct AnswerverifiedShow Answer

In order for a CT x-ray photon to be measured, it must 1) enter the detector 2) be absorbed by the detector material 3) transmit through the detector to be back-projected 4) have sufficient energy to undergo a Compton interaction 5) be converted to light and then electrical energy as a signal

Correct AnswerverifiedB

Modern pulsed CT scanners operate at

Correct AnswerverifiedShow Answer

The most recent generation of CT scanners use a ____ motion.

Correct AnswerverifiedShow Answer

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A

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C

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B

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