Quiz Flashcards
In order for an X-ray photon to be measured it must:
1. Enter the detector chamber
2. Be absorbed by the detector material
3. Be converted to a measurable event
A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3
D
Which system component converts the projection attenuation data into the proper digital form for the array processor?
A. Detector
B. Photodiode
C. Analog-to-digital converter
D. Host computer
C
Which of the following is NOT a function of a PACS system?
A. Reconstruction of the image from the raw data
B. Long term data storage
C. Digital distribution of images
D. Image display for the radiologists
A
Which part of the following is NOT part of the CT tube?
A. Tungsten target
B. Collimation
C. Rotating anode
D. Filament
B
Which of the following is FALSE regarding CT systems?
1. They are limited to non-oblique transverse scanning
2. They cannot generate a straight coronal or sagittal image
3. They have no moving parts
A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3
D
X-rays are used in CT because:
A. They are easily produced by the high frequency generator
B. They are less harmful than the heating effects of microwave radiation
C. They penetrate the body according to specific attenuation characteristics of each tissue
D. The FDA imposes no limit on the dose to the patient
C
Most of the commands from the technologist are received by the:
A. Array processor
B. Operator’s console
C. Host computer
D. Amplifier
B
X-rays are produced whenever fast-moving electrons collide with any form of matter because:
1. The electron splits into two x-ray photons of equal energy upon impact with the matter
2. The electron loses kinetic energy which is converted into the emission of an x-ray photon
3. The electron converts the electron it collided with into an x-ray photon
A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3
B
The mA determines the:
A. Quantity of x-ray photons
B. Coefficient of attenuation
C. Slice thickness
D. Energy level of the x-ray photons
A
Which of the following is a component NOT normally located in the gantry of a modern CT system?
A. Pre-patient collimation
B. Solid-state detectors
C. Array processor
D. X-ray tube
C
Tube interscan delay time refers to:
A. The time between the end of one scan and the start of the next scan during which the tube will cool
B. A quality assurance test performed daily by the technologist
C. The time required for the tube to make a complete 360* revolution about the gantry
D. The length of time required for the production of photons to begin after applying the voltage to the tube
A
Increased _________ will increase the likelihood that a given x-ray will penetrate a material.
1. kV
2. mA
3. Exposure time
A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3
A
Which of the following are NOT commonly used on today’s commercially available CT scanners?
1. Xenon detectors
2. Fourth-generation technology
3. Continuous rotation technology
A. 1 only
B. 1 & 2
C. 2 & 3
D. 1, 2, & 3
B
Which of the following statements is FALSE regarding occurrences after an x-ray photon penetrates the detector aperture?
1. The photon can pass through the detector unmeasured
2. The photon is converted completely into an electron
3. The measured signal is enhanced by an amplifier
A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3
B
Scatter radiation is caused by:
A. A miscallibrated detector
B. X-rays generated spontaneously in the ambient atmosphere
C. Deflections from the original trajectory of an x-ray photon through the patient
D. Improper patient positioning
C
What control does the operator have over the x-rays in a CT exam?
A. The temperature and color of the x-rays can be tuned
B. The energy level and the quantity of x-rays can be selected
C. The volume and tone of the x-rays can be dialed
D. The phase and frequency of the x-rays can be adjusted
B
Which of the following is the standard that’s used to achieve compatibility for image transfer between various imaging modalities, viewing stations, and printers in a hospital?
A. TCP/IP
B. T1
C. PACS
D. DICOM
D
The enormous heat that builds up in the CT tube is caused by the:
A. Intensity of the x-rays emitted from the tube
B. Electron beam between the cathode and the anode in the tube
C. X-ray filter in the tube which absorbs the lower energy photons before they can enter the patient
D. collision of the electron beam with the tungsten target on the tube anode
D
______________ made helical imaging possible.
A. Multi-row detector scanners
B. Electron beam between the cathode and the anode in the tube
C. X-ray filter in the tube which absorbs the lower energy photons before they can enter the patient
D. Collision of the electron beam with the tungsten target on the tube anode
D
The patient table:
A. May move continuously during the scan
B. Can never be positioned automatically by software due to safety precautions
C. Remains stationary throughout the patient exam once it is initially positioned
D. Only moves after each slice is completed
A
The main purpose of the detector is to:
A. Provide additional collimation in order to reduce scatter
B. Limit the x-ray dose o the patient
C. Capture x-ray photons and convert them to a measurable signal
D. Amplify the measured signal
C
The cathode filament:
A. Helps determine the size of the focal spot
B. Lights up the tube so it can be serviced by an engineer
C. Releases the x-ray photons
D. Focuses x-rays onto the anode target
A
Which of the following statements is TRUE?
1. kV is the voltage potential between the tube cathode and anode while mA ultimately controls the filament current and, thus, the temperature of the cathode filament
2. kV controls the energy level of the x-ray photons and mA controls the number of x-ray photons emitted from the tube
3. Although the kV and the mA affect the operation of the CT x-ray tube, the two parameters have no bearing on the image quality
A. 1 only
B. 2 only
C. 1 & 2
D. 2 & 3
C
The number of electrons that flow from the cathode to the anode in the tube is controlled by the:
A. Anode target
B. Collimation
C. mA
D. kV
C
