CT
The range of CT numbers or Hounsfield units varies from: 100 to 300 -100 to +300 -1000 to +3000 1000 to 3000
-1000 to +3000
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
1 enter the detector 2 be absorbed by the detector material,5 be converted to light and then electrical energy as a signal
Who is credited with designing the first medical CT scanner in the 1970s? Joseph Radon William Oldendorf Godfrey Hounsfield Wilhelm Roentgen
Godfrey Hounsfield
The ______________ ___________________ is how well the detectors detect the incoming photon energy. response time conversion efficiency capture efficiency absorption efficiency
absorption efficiency
Modern pulsed CT scanners operate at: 120 kVp 1 to 5 msec pulses 1000 mA all of the above
all of the above
The CT console provide the radiographer access to: the software program table movement gantry tilt all of the above
all of the above
The CT table is: made of carbon graphite rated for maximum weight motor driven all of the above
all of the above
A ____________ artifact is caused by attenuation of the beam as it passes through the patient. A.partial volume effect B.ring C.star D.beam hardening
beam hardening
The process of combining detector elements into various combinations in order to set slice thickness is called detector ____________. partitioning interpolation binning modulation
binning
The ___________ ______________ is how well the detectors receive photons from the patient. absorption efficiency conversion efficiency capture efficiency response time
capture efficiency
Which of the following is best described as the body plane that divides the body vertically, front from back? axial coronal transverse saggital
coronal
What is the term that best describes the IR in CT? detector monitor filter collimator
detector
What CT imaging characteristic allows for image differentiation among different tissue types? excellent contrast resolution excellent analog to digital convertor excellent visibility of detail excellent spatial resolution
excellent contrast resolution
The most recent generation of CT scanners use a ____ motion. helical translate-rotate rotate-translate elliptical
helical
This occurs when small structures lose detail in large volume areas. A.partial volume effect B.ring C.star D.beam hardening
partial volume effect
How is helical scan pitch best described? ratio of the distance the table moves to the number of times the tube travels around the patient ratio of distance the table moves to the scan time ratio of the distance the table moves to the amount of pre and post collimation ratio of the distance the table moves to the beam width during one revolution of tube travel
ratio of the distance the table moves to the beam width during one revolution of tube travel
A _____________ artifact is caused by detector error. A.partial volume effect B.ring C.star D.beam hardening
ring
Which of the following is best described as the body plane that divides the body longitudinally, right from left? transverse oblique coronal sagittal
saggital
A ____________ artifact is caused by the presence of metal in the patient. A.partial volume effect B.ring C.star D.beam hardening
star
What is the primary advantage of CT over conventional digital radiography? optimum spatial resolution the ability to overcome the superimposition of structures decreased time of procedure less radiation dose
the ability to overcome the superimposition of structures
Computed tomography sections are acquired in the __________ plane. coronal sagittal orthogonal transverse
transverse
Which of the following is best described as the body plane that divides the body into superior and inferior parts? oblique coronal sagittal transverse
transverse
The gantry of the CT unit contains the post processing workstation operator's interface x-ray tube all of the above
x-ray tube