CT Instrumentation part 2 Flashcards

1
Q

What is the word for CT that corresponds to the bore size in MR?

A

The gantry aperture

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2
Q

How much can CT gantries tilt?

A

12 - 30 degrees

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3
Q

What is the frequency range for the high frequency generators used in modern CT scanners?

A

500 - 25,000 Hz

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4
Q

How many degrees angled is the high speed rotating anode in the CT x-ray tube?

A

12 degree target angle

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5
Q

What part of the CT system has Ceramic Elements?

A

the Solid State detectors used in multi-slice CT

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6
Q

What is the common name for “axial” CT image acquisition that we use here for Iaia’s head scans.

A

Step-and-shoot

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7
Q

Speed and Accuracy are two important features of this “A” acronym that is part of the CT imaging system.

A

ADC (or Analog to Digital Converter)

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8
Q

What is the relationship between the number of “bits” of the ADC processor and it’s accuracy?

A

The high the “bits” the more accurate the it is and the more shades of gray represented

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9
Q

What is the relationship between ADC (analog to digital converter) speed and accuracy?

A

They are inversely proportional. As one increases, the other decreases (ie. increased accuracy = slower digitization)

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10
Q

Increased ADC speed (results in slower digitization, results in increased accuracy in the digitization process, results in decreased accuracy in the digitization process, requires a fewer bit processor)

A

Results in decreased accuracy in the digitization process

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11
Q

The ability of a detector to capture, absorb, and convert photons is referred to as: (detector response time, detector stability, the dynamic range of the detector, detector efficiency)

A

Detector efficiency

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12
Q

The circular opening of the gantry through which the patient travels in a CT scanner is termed: (gantry collimator, gantry aperature, gantry tilt, gantry range)

A

Gantry aperature

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13
Q

The gantry is equipped with _____ technology for the purpose of centering and positioning the patient for a CT exam.

A

Laser Beam

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14
Q

The typical range of gantry tilt in a CT scanner is ______. (1 - 5 degrees, 5 - 10 degrees, 10 - 15 degrees, 12 - 30 degrees).

A

12 - 30 degrees

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15
Q

What type of detector is used in a multi-slice CT scanner? (xenon detector, flat panel detector, scintillation detector, dosimetry detector)

A

Scintillation Detector

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16
Q

The type of multi-slice detector called an adaptive array in which the individual detector cells are divided into different sizes is called: (xenon detector, symmetric detector, matrix detector, asymmetric detector)

A

Asymmetric detector

17
Q

What 3 functions does the computer system do with data?

A

Received data, reconstructs data, manipulates data (raw and image)

18
Q

CT Computers have a special processor called “LAPP”. What does it stand for?

A

Large Array Parallel Processor

19
Q

What is the main goal of pre-processing software?

A

To remove unwanted signals prior to image reconstruction

20
Q

What is the ultimate goal of the reconstruction software?

A

assigning CT Numbers

21
Q
  1. Iterative Methods (Algebraic Reconstruction Technique [ART] used by Hounsfield, Iterative Least Squares [ILST], Simultaneous Iterative Reconstruction Technique), 2. Back Projection, 3. Analytical Method (filtered Back Projection, Two-dimensional Fourier Transformation) are the three main kinds of _______.
A

Reconstruction Algorithms

22
Q

What scanner generation were iterative reconstruction methods used?

23
Q

What type of reconstruction algorithm is prone to Star Pattern Noise?

A

Back Projection

24
Q

Of the three major reconstruction algorithms, which is in use today?

A

Analytical method (filtered back projection or interpolation algorithms)

25
In what kind of scaning are interpolation algorithms used?
Helical or Spiral scanning
26
The part of the central processing unit that directs the activities of the computer is called the: (arithetic unit, control unit, input unit, logic unit)
Control Unit
27
The part of a computer system that is the center of all activities or "the thinker" is called the: (CPU, ALU, Control unit, Output Unit)
CPU
28
The industry standard format for radologic images is:
DICOM