Special Imaging Procedures
The range of CT numbers or Hounsfield units varies from
-1000 to +3000
Modern pulsed CT scanners operate at:
120 kVp 1 to 5 msec pulses 1000 mA
The CT table is
Carbon graphite, rated for max weight and motor driven.
Who is credited with designing the first medical CT scanner in the 1970s?
Godfrey Hounsfield
The ______________ ___________________ is how well the detectors detect the incoming photon energy.
absorption efficiency
A ____________ artifact is caused by attenuation of the beam as it passes through the patient
beam hardening
The process of combining detector elements into various combinations in order to set slice thickness is called detector ____________.
binning
The ___________ ______________ is how well the detectors receive photons from the patient.
capture efficiency
Which of the following is best described as the body plane that divides the body vertically, front from back?
coronal
What is the term that best describes the IR in CT?
detector
In order for a CT x-ray photon to be measured, it must
enter the detector, be absorbed by the detector material, be converted to light and then electrical energy as a signal
What CT imaging characteristic allows for image differentiation among different tissue types?
excellent contrast resolution
The most recent generation of CT scanners use a ____ motion.
helical
This occurs when small structures lose detail in large volume areas.
partial volume effect
How is helical scan pitch best described?
ratio of the distance the table moves to the beam width during one revolution of tube travel
A _____________ artifact is caused by detector error.
ring
Which of the following is best described as the body plane that divides the body longitudinally, right from left?
sagittal
The CT console provide the radiographer access to:
software program, table movement, gentry
A ____________ artifact is caused by the presence of metal in the patient.
star
What is the primary advantage of CT over conventional digital radiography?
the ability to overcome the superimposition of structures
Computed tomography sections are acquired in the __________ plane.
transverse
Which of the following is best described as the body plane that divides the body into superior and inferior parts?
transverse
The gantry of the CT unit contains the
x-ray tube
