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100 terms

Ch 3 Review of Equipment Operation and Quality Control

STUDY
PLAY
In many cases, digital fluoroscopy eliminates what?
Postprocedure "overhead" films
A photostimulable phosphor is the active component of what piece of quipment?
Computed radiography imaging plate
In computed radiography, the image must be turned into digital form by what device?
Analog-to-digital converter
A mathematical formula used to recontruct the image in digital imaging is called:
An algorithm
Picture elements in a digital image are called:
Pixels
A digital image is composed of rows and columns known as a:
Matrix
Direct digital radiography differs from computed radiography in what way?
The use of fixed detectors that communicate directly with the computer
Window width in computed radiography and digital radiography controls what image property?
Contrast
A graphic display that is constructed to show the radiographer the distribution of pixel values is called:
A histogram
The law stating that the oouter shell of an atom can contain no more than eight electrons is called:
Octet Rule
Examples of particulate radiation are:
Helium nuclei and beta particles
Electromagnetic radiation travels:
In waves along a straight path
Electromagnetic raiation travels in bundles of energy called:
photons
X-rays travel at what speed?
The speed of light, 186,000 miles per second
Waves of radiation are called:
Sine waves
Wavelength is defined as the distance from:
Peak to peak of the wave
Frequency is defined as:
The number of waves passing a point per unit time
The speed of w-rays is based on:
The fact that they are a form of electromagnetic radiation
Wavelength and frequency are:
Inversely proportional to each other
The x-ray beam will change as it travels through th patient by a process called:
Attenuation
The intensity of radiation is inversely proportional to the square of the distance between the source of radiation and the person receiving it . This descibes:
Inverse square law
As radiation strkes matter:
The energy is transferred to the atoms according to the law of conservation of energy
Which of the statements are true regarding electrostatic charges?
1) Electrostatics is the study of electirc chares at rest
4) Electrostatic charges concentrate on a conductor in the area of greatest curvature
Which of the statements are false regarding Equipment Operation?
4) The volt is the unit of electric curretn
6) The ampere is the unit of electromotive force
9) Ohm's law is calculated unsing the quation VI=R
Electromagnetic induction is the process of causing an electric current to flow in a conductor:
When it is placed in the magnetic field of another conductor
The two types of electromagnetic induction are:
Self-induction and mutual induction
Self-induction is used in the operation of what device?
Autotransformer
The strength of the magnetic fields in a transformer is increased by:
Coiling the vires and letting their magnetic fields overlap
Electricity is supplied to the imaging department by a:
Generator
The electricity provided to the radiology department is:
60 Hz Ac
The electricity provided to the radioglody department operates at:
120 pulses per second
High-frequency power:
Has almost no ripple
The primary advantage of three-phase power is that:
Voltage never drops to zero
A variable transformer that is used to select kVp for the x-ray circuit is the:
Autotransformer
A transformer that has more turns in the secondary than in the prmary coild is called a:
Step-up transformer
The transformer used to boost voltage to kilo-voltage levels is called a(n):
Step-up transformer
Voltage coming to the x-ray machine is kept constant through the use of a(n):
Line voltage compensator
A step-down transformer:
Steps down voltage
Where does thermionic emission occur?
Cathode
What device is prereading?
kVp meter
What device reduces voltage and provides current to produce an electron cloud or space charge at the filament?
Step-down transformer
What device is electronic, with increments as low as 0.001 second?
Timer
What changes AC to DC?
Rectifier
What is surrounded by a negatively charged focuing cup?
Filament
What is composed of solid-state, silicon-based diodes?
Rectifier
What regulates the duration of x-ray production?
Timer
What is located in the x-ray circuit between the high-voltage tranformer and the x-ray tube?
Rectifier
What measures tube current?
mA meter
What device spines at 3300 to 10,000 rpm?
Anode
What device uses maximum heat storage ability of the tube to deliver mAs?
Falling load generator
What is the source of bremsstrahlung and characteristic rays?
Anode
What device increases voltage approximately 500 times?
Step-up transformer
What is the most commonly used AEC?
Ionization Chamber
What device always delivers the shortest exposure time possible?
Falling load generator
What device is turned by a rotor?
Anode
Which of the following is located between the patient and the image receptor?
Ionization chamber
The filament is kept warm by:
A standby current from the time the x-ray machine is turned on
Activating the rotor will:
Reduce tube life
When making an exposure, the radiographer should:
Activate the rotor and exposure switch in one continuous motion
The process of thermionic emission causes:
Electrons to boil off the filament
The electron stream passes from cathode to anode because of ______ passing through the x-ray tube.
Current
Heat is produced in the x-ray tube as:
Electrons interact with the target material
Most of the energy conversion in the x-ray tube produces:
heat
X-rays are produced as incident electrons interact with target atoms by a process called:
Brensstrahlung
X-rays are produced as incident electrons interact with inner shell electrons in target atoms by a process called:
Characteristic
What percentage of energy in the x-ray tube is converted to x-rays?
1 %
What are properties of x-rays?
2) Affect film emulsion
3) scatter and produced secondary radiation
4) Invisible
7) Travel in bundles called photons
8) Ionize matter and gases
10) cause phosphors to fluoresce
The x-ray beam is:
Hetergeneous or polyenergetic, consisting of many different energies (wavelengths)
The x-ray emission spectrum consists of:
Discrete spectrum (produced by characteristic rays) and continuous spectrum (produced by brems rays)
The primary purpose of filtration is:
Radiation protection
The amount of material needed to reduce the intensity of the beam by 1/10 is called:
Tenth-value layer
What statements are true regarding filtration?
Total filtration (not less that 2.5-mm aluminum equivalent) = inherent filtration (glass envelope, tube housing, oil) + added filtration (aluminum)
Calculating heat untties for three-phase, twelve-pulse quipment requires the use of ____ as a constant; calculating heat units for single-phase equipment requires the use of _____ as a constant; calculating heat units for three-phase, six-pulse equipment requires the use of _____ as a constant.
1.41, 1, 1.35 because average photon energy is different with each type of equipment
Which of the following charts may be consulted to determine the safety of a single x-ray exposure?
Tube rating chart
Which of the following charts may be consulted to determine the safety of a series of x-ray exposure?
Anode cooling curve
The portion of the image intensifire tube that converts elctron energy to visible light is the :
Output phoshor
The portion fo theII tube that converts visible light to an electronic image is the:
Photocathode
The input phosphor of the image-intensifier tube converts:
xray evergy to visible light
Total brightness gain achieved using an image intensifier equals:
flux gain times minification gain
Single-phase, full-wave rectification produces:
Pulsating direct current with 120 pulses per sec and 100%
Three-phase, six-pulse full-wave rectification produces:
DC with 13% ripple
Three-phase, twelve-pulse full-wave rectification produces:
DC with 4% ripple
The increase in average photon evergy when using three-phase, six-pulse equipment compared with single-phase equipment is:
35%
The increase in average photon energy when using three-phase, 12-ulse quipment compared with single-phase equipment is:
41%
Programs that deal with the safe and reliable operation of equipment and those that adress all aspects of the delivery of radiology services are called, respectively:
Quality control and qulity assurace
Eamples of dedicated x-ray equipment include:
mammo, tomo. mobile units
The collimator must be accurate to a level of :
2% of SID
kVp must be accurate to within:
4
Exposure linearity must be accurate to within:
10%
Exposure reproducibility must be accurate to within:
5%
When a spinning top test is performed on single-phase equipment , a radiograph exhibting four dots would indicate:
An accurate timer, if set on 1/30 second
When a spinning top test is performed on three-phase equipment, a timer setting of 1/60 sencond should indicate the following on the resultant radiograph:
a 6-degree arc
The test that measures the accuracy of adjacent mA stations is :
Exposure Linearity
The test that measures the accuracy of successive exposures is:
Exposure Reproducibility
Effective focal-spot size may be measured using the followin tools
slit camera, star test pattern, pinholde camera
Resolution of the television system by be measured ising the following tools
resolution test pattern
Automatic exposure controls may be tseted using:
Phantoms
The amount of mA used for fluoroscopy is:
3 to 5
Marks on the focal track of the anode resulting from bombardment of electrons are called:
Pitting
Effective quality control and quality assureance programs are requiresd for accreditation by:
The Joint Commission