Prep
Which of the following reduces the scatter radiation reaching the detectors?
A. Post-patient collimation
B. Pre-patient collimation
C. Pre-detector collimation
D. Both A & C -D. Both A & C
Which of the following is the primary interaction between x-ray photons and tissue during computed
tomography?
A. Bremsstrahlung
B. Characteristic
C. Compton effect
D. Coherent scatter -C
The process by which electrons are produced at the cathode of a CT x-ray tube is known as:
A. rectification
B. anode heel effect
C. thermionic emission
D. isotropic emission -C
The assignment of different generations to CT scanners is based on the configuration of the:
A. patient and gantry
B. tube and detectors
C. anode and cathode
D. tube and collimators -B
When one is using a third-generation CT scanner, it is important that reference detectors positioned at the
peripheral portions of the detector array be exposed to:
A. homogeneous radiation
B. unattenuated radiation
C. monochromatic radiation
D. remnant radiation -D
, In 1979, the scientists __________ and __________ shared the Nobel Prize for their research in
computed tomography
A. Watson and Crick
B. Olendorf and Hounsfield
C. Hounsfield and Cormack
D. Hounsfield and Ambrose -C
The type of compensating filter used at the x-ray tube of a CT scanner is called a:
A. kernel
B. water bath
C. bow-tie filter
D. wedge filter -C
The interaction between x-ray and matter that is responsible for the production of the scatter radiation
absorbed by the patient and detectors is:
A. Compton effect.
B. bremsstrahlung.
C. photoelectric.
D. characteristic -A
The types of detectors used in computed tomography are:
1. Gas ionization
2. Stimulable phosphor
3. Scintillation
A. 1 only
B. 3 only
C. 1 and 3 only
D. 2 and 3 only -C
Which of the following is used in gas ionization CT detectors?
A. Neon
B. Xenon
C. Helium
D. Nitrogen -B
Which of the following statements concerning the translate-rotate mode of CT data acquisition is/are
correct?
1. 360-degree circular detector arrays are used.
2. Data are collected only during translation.
3. Was used in first- and second-generation CT scanners.
A. 2 only
B. 3 only
C. 1 and 2 only
D. 2 and 3 only -D
Which of the following terms accurately describes the type of x-ray beam used in a third-generation CT
scanner?
A. Pencil beam
B. Fan beam