PET/CT MIDTERM| 99 QUESTIONS AND
ANSWERS 100% CORRECT
Explain the meaning of pitch - ANSWER-The table movement of the patient going
through the gantry. The smaller the pitch the longer the scan time and increased patient
dose there is. If the pitch is bigger then it can cause gaps and miss sections of the body
that are needing to be imaged and also degrades contrast.
What is the purpose of windowing (window level and window width) of a set of CT
images? - ANSWER-Allowing the certain tissue to be displayed while the other values
(HU) that are below and above the set window to be out of range with lower intensity.
CT voxel values are given in terms of _______________
, which express the attenuation of a given tissue relative to that of ____________. -
ANSWER-Hounsfield units, water
The two types of x-rays produced in an x-ray tube are
and _____________. - ANSWER-Characteristic, Bremssstrahlung
The x-ray beam used for CT imaging is polychromatic. (True or false) - ANSWER-True
A larger value for pitch indicates higher radiation exposure to the patient. (True or false)
- ANSWER-False
All of the following are true about increasing the kVp setting EXCEPT
A. it selects the maximum possible energy of the x-ray beam
B. it defines the fraction of photons that will reach the detectors
C. it affects the radiation exposure to the patient
D. it increases beam hardening - ANSWER-D. it increases beam hardening
Modern CT scanners rely on _____ to process acquired data.
A. supercomputers
B. mainframe computers
C. minicomputers
D. microcomputer - ANSWER-C. minicomputers
To assure fast scan times and immediate data processing, CT computers depend on:
A. distributed processing.
, B. multitasking
C. multiprocessing
D. parallel processing. - ANSWER-D. parallel processing
Large array parallel processors are responsible for:
A. executing several tasks sequentially.
B. performing numerous tasks simultaneously .
C. assessing faulty detector arrays
D. hardening the x-ray beam. - ANSWER-B. performing numerous tasks simultaneously
Collimators in CT scanning are used to do all of the following EXCEPT
A. limit the beam size
B. reduce scattered x-rays
C. define slice thickness
D. offset the alignment of the tube and detector array to optimize the beam location -
ANSWER-D. offset the alignment of the tube and detector array to optimize the beam
location
Computed tomography (CT) scanning accomplishes all of the following EXCEPT
A. minimal superimposition of tissues
B. improved contrast resolution
C. reduction of radiation dose compared to conventional radiography
D. differentiation of tissue densities - ANSWER-C. reduction of radiation dose
compared to conventional radiography
In a CT scanner, the oil bath that may surround the rotating anode tubes serves to
A. make the tubes rotate more quickly
B. make the tubes rotate more smoothly
C. cool the tubes
D. provide efficient conduction of the current - ANSWER-C. cool the tubes
In an x-ray tube, of the energy applied to the system, the percentage of x-rays that exit
is
A. 1%
B. 10%
C. 50%
D. 99% - ANSWER-A. 1%
The purpose of using an aluminum filter in CT scanning is
A. to absorb the very-low-energy x-rays
ANSWERS 100% CORRECT
Explain the meaning of pitch - ANSWER-The table movement of the patient going
through the gantry. The smaller the pitch the longer the scan time and increased patient
dose there is. If the pitch is bigger then it can cause gaps and miss sections of the body
that are needing to be imaged and also degrades contrast.
What is the purpose of windowing (window level and window width) of a set of CT
images? - ANSWER-Allowing the certain tissue to be displayed while the other values
(HU) that are below and above the set window to be out of range with lower intensity.
CT voxel values are given in terms of _______________
, which express the attenuation of a given tissue relative to that of ____________. -
ANSWER-Hounsfield units, water
The two types of x-rays produced in an x-ray tube are
and _____________. - ANSWER-Characteristic, Bremssstrahlung
The x-ray beam used for CT imaging is polychromatic. (True or false) - ANSWER-True
A larger value for pitch indicates higher radiation exposure to the patient. (True or false)
- ANSWER-False
All of the following are true about increasing the kVp setting EXCEPT
A. it selects the maximum possible energy of the x-ray beam
B. it defines the fraction of photons that will reach the detectors
C. it affects the radiation exposure to the patient
D. it increases beam hardening - ANSWER-D. it increases beam hardening
Modern CT scanners rely on _____ to process acquired data.
A. supercomputers
B. mainframe computers
C. minicomputers
D. microcomputer - ANSWER-C. minicomputers
To assure fast scan times and immediate data processing, CT computers depend on:
A. distributed processing.
, B. multitasking
C. multiprocessing
D. parallel processing. - ANSWER-D. parallel processing
Large array parallel processors are responsible for:
A. executing several tasks sequentially.
B. performing numerous tasks simultaneously .
C. assessing faulty detector arrays
D. hardening the x-ray beam. - ANSWER-B. performing numerous tasks simultaneously
Collimators in CT scanning are used to do all of the following EXCEPT
A. limit the beam size
B. reduce scattered x-rays
C. define slice thickness
D. offset the alignment of the tube and detector array to optimize the beam location -
ANSWER-D. offset the alignment of the tube and detector array to optimize the beam
location
Computed tomography (CT) scanning accomplishes all of the following EXCEPT
A. minimal superimposition of tissues
B. improved contrast resolution
C. reduction of radiation dose compared to conventional radiography
D. differentiation of tissue densities - ANSWER-C. reduction of radiation dose
compared to conventional radiography
In a CT scanner, the oil bath that may surround the rotating anode tubes serves to
A. make the tubes rotate more quickly
B. make the tubes rotate more smoothly
C. cool the tubes
D. provide efficient conduction of the current - ANSWER-C. cool the tubes
In an x-ray tube, of the energy applied to the system, the percentage of x-rays that exit
is
A. 1%
B. 10%
C. 50%
D. 99% - ANSWER-A. 1%
The purpose of using an aluminum filter in CT scanning is
A. to absorb the very-low-energy x-rays
