CT
The ____ is how well the detectors receive photons from the patient. A. Capture efficiency B. Absorption efficiency C. Conversion efficiency D. Response time
A. Capture efficiency
First-generation CT scanners scanned the ____ only. A. Head B. Thorax C. Abdomen D. Pelvis
A. Head
A series of tissue density values that evolved for CT measurements is called ____ units. A. Hounsfield B. H & D C. Attenuation D. Iterative
A. Hounsfield
A series of tissue density values that evolved for CT measurements is called ____ units. A. Hounsfield B. H & D C. Attenuation D. Iterative
A. Hounsfield
The ability of the gantry to rotate continuously for helical scanning is made possible with: A. Slip rings B. Recoiling cables C. Aperatures D. Detectors
A. Slip rings
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 A. 1, 3, 4 AND 5 B. 1, 2 AND 5 C. 1, 2 AND 4 D. 1, 4 AND 5
B. 1, 2 AND 5
The ____ is how well the detectors convert incoming photons. A. Capture efficiency B. Absorption efficiency C. Conversion efficiency D. Response time
B. Absorption efficiency
What is the name of the system that measures the photons striking the detector, converts it to a digital signal, and then sends that signal to the computer? A. Digital acquisition B. Data acquisition system C. Analog to digital system D. Detector acquisition system
B. Data acquisition system
On CT images there must be a _______ difference in order to see adjacent structures. A. Contrast B. Density C. Detail D. Object
B. Density
Who was the first to incorporate digital imaging with the CT scanner? A. Paul Lauterbur B. Godfrey Hounsfield C. Sol Nudelman D. M. Paul Capp
B. Godfrey Hounsfield
The most recent generation of CT scanners use a ____ motion. A. Translate-rotate B. Helical C. Linear D. Elliptical
B. Helical
Contemporary CT scanners use solid state detectors. These detectors utilize A. Sodium iodide crystals B. Rare earth ceramic scintillators C. Xenon gas D. Freon gas
B. Rare earth ceramic scintillators
All of the data acquired by the CT system with each scan is termed: A. Image data B. Raw data C. Helical data D. Axial data
B. Raw data
CT image data is acquired in the 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.
B. Transverse plane and reconstructed in any plane.
The reference material for CT is ____ and is related to the ____ of the tissue. A. Water, field of view B. Water, linear attenuation coefficient C. Muscle, gray level D. Bone, mass attenuation
B. Water, linear attenuation coefficient
The range of CT numbers or Hounsfield Units varies from A. 100 to 300 B. -100 to +300 C. -1000 to +3000 D. 1000 to +3000
C. -1000 to +3000
CT scan pitch uses all of the following technical parameters EXCEPT A. Slice thickness B. 360-degree gantry rotation C. Acquisition mAs D. Table increment
C. Acquisition mAs
The calculation of CT numbers is based upon the calculation of A. Half-value layers B. Half-lives C. Attenuation coefficients D. Pitch
C. Attenuation coefficients
The ____ is determined by how well the detector converts the absorbed photon information to a digital signal for the computer. A. Capture efficiency B. Absorption efficiency C. Conversion efficiency D. Response time
C. Conversion efficiency
Early reconstruction of raw CT data took a few ______ to form a recognizable image. A. Minutes B. Hours C. Days D. Months
C. Days
Which of the following houses all of the components of a CT system to produce and detect x-rays? A. Slip rings B. Table C. Gantry D. Generator
C. Gantry
The units that quantify the degree of structure attenuation in CT is: A. Rads B. Rems C. Hounsfield D. Sieverts
C. Hounsfield
CT is able to differentiate between tissues with similar densities compared with conventional radiography due to: A. Digital magnification B. The use of a computer for data processing C. Improved contrast resolution D. Axial slices
C. Improved contrast resolution
An array of numbers arranged in a grid of rows and columns is called a: A. Pixel B. Voxel C. Matrix D. Scan profile
C. Matrix
To achieve coronal or sagittal sections, A. The gantry is repositioned. B. The patient is repositioned. C. Reconfiguration software is implemented. D. None of the above
C. Reconfiguration software is implemented.
The localization image produced by the CT scanner is technically called a/an A. Volume rendered image B. Scout film C. Scanogram D. FOV image
C. Scanogram
Which modality was the first to use the principle of digital imaging? A. Computed tomography (CT) B. Magnetic resonance imaging (MRI) C. Ultrasonography D. Cardiac catheterization
C. Ultrasonography
The gantry of the CT unit contains the A. Post processing workstation B. Operator's interface C. X-ray tube D. All of the above
C. X-ray tube
The gantry of the CT unit contains the A. Post-processing workstation B. Operator's interface C. X-ray tube D. All of the above
C. X-ray tube
Computed tomography sections are available as A. Coronal B. Transverse C. Sagittal D. All of the above
D. All of the above
Computed tomography sections are available as A. Coronal B. Transverse C. Sagittal D. All of the above
D. All of the above
Modern pulsed CT scanners operate at A. 120 kVp B. 1 to 5 msec pulses C. up to 1000 mA D. All of the above
D. All of the above
The CT console provides the radiographer access to A. The software program B. Data acquisition C. Data display D. All of the above
D. All of the above
The CT radiation beam is collimated A. At the tube exit B. At the detector entrance C. Pre-patient and post-patient D. All of the above
D. All of the above
The CT table is A. Made of carbon graphite B. Rated for maximum weight C. Motor-driven D. All of the above
D. All of the above
The resolution of the CT image depends on the A. Pixel B. Voxel C. Matrix size D. All of the above
D. All of the above
The smaller the scan field size, the A. Better the resolution B. Faster the scan time C. Less the risk of motion D. All of the above
D. All of the above
The degree to which an x-ray beam is absorbed by an object is known as: A. Collimation B. Volume averaging C. Beam restriction D. Attenuation
D. Attenuation
The primary mathematical method used in the creation of computerized medical images is the ____ transformation. A. Interpolation B. Hounsfield C. Algorithm D. Fourier
D. Fourier
