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WorksheetsHESI image production
Total questions: 52
Worksheet time: 47mins
In many cases, digital fluoroscopy eliminates which of the following?
The need for a radiographer
Postprocedure “overhead” images
Image acquisition
Accurate positioning
What is the smallest particle of an element that retains the characteristics of the element?
Mole
Atom
Molecule
Quark
In digital fluoroscopy, the image must be turned into digital form by what device?
Digital-to-analog converter
Flux capacitor
Analog-to-digital converter
DVD-ROM
X-rays travel as bundles of energy called:
Energy waves
Phasers
Electromagnetic bursts
Photons
What is atomic mass?
The number of protons plus the number of neutrons
The number of photons
The number of electrons
The number of protons plus the number of electrons
What device may be used to ensure consistency of radiographic quality from one exposure to the next?
Electronic timer
Step-up transformer
Automatic exposure control
High-frequency generator
When a predetermined level of ionization is reached in the ionization chamber, what does the machine do?
The unit shuts off as a result of a malfunction
The maximum allowable time has been reached
The highest allowable dose to the patient has been reached
The exposure is terminated
What type of x-ray machine uses a continually decreasing mA for the shortest times possible?
Ionization chamber
Portable
C-arm
. Falling load generator
What type of current is required for proper operation of the x-ray tube?
Direct
Falling load
Alternating
Fluctuating
The law stating that the outer shell of an atom can contain no more than eight electrons is called:
Ohm’s law
Octet rule
Octagon rule
Electron binding energy
Examples of particulate radiation are:
X-rays, gamma rays, and cosmic rays
Helium nuclei and beta particles
Electrons, protons, and meteorites
X-rays and quarks
Electromagnetic radiation travels:
In waves along a straight path
. In circles
Back and forth
As electrons in waves along a straight path
The latest digital fluoroscopic units use:
Nonionizing radiation
CR cassettes
Conventional image intensifiers
Flat panel plates similar to DR
At what speed do x-rays travel?
The speed of light—186,000 miles per hour
The speed of the incident electrons—93,000 miles per second
The speed of light—186,000 miles per second
Infinite speed
Waves of radiation are called:
Sine waves
Strong waves
Signal waves
Current waves
Wavelength is defined as the distance from:
The x-ray tube to the patient
The cathode to the anode
The bottom of a wave to the top
Peak to peak of the wave
Frequency is defined as
Synonymous with wavelength
The number of waves passing a point per unit time
The number of waves striking the patient
The number of exposures needed during an exam
The speed of x-rays is based on:
mAs
kVp
The size of the patient
The fact that they are a form of electromagnetic radiation
Wavelength and frequency are:
Directly proportional to each other
Inversely proportional to each other
Inversely proportional to the square of their distance
Unrelated to each other
The x-ray beam changes as it travels through the patient by a process called:
Filtration
Attenuation
Electrification
Annihilation
The intensity of radiation is inversely proportional to the square of the distance between the source of radiation and the person receiving it. This describes the:
Square law
Reciprocity law
Inverse square law
Octet law
As radiation strikes matter:
The energy of the rays is destroyed
The energy of the rays is increased as they acquire the energy of the atoms
The energy is transferred to the atoms according to the law of conservation of energy
The energy is converted to matter according to Einstein’s theory
Which of the following statements are accurate regarding electrostatic charges? (Select 2)
Electrostatics is the study of electric charges at rest
The movement of electrons from one object to another is called ionization
. Like charges attract, and unlike charges repel
Electrostatic charges concentrate on a conductor in the area of greatest curvature
Friction, contact, and induction are methods of ionization
Which of the following are accurate? (Select all that apply.)
A magnetic field always surrounds an electrical charge in motion
Current flows back and forth in AC
Current flows in one direction in DC
The path of electrical current is called the circuit
The path of electrical current is called the circuit
Electromagnetic induction is the process of causing an electrical current to flow in a conductor:
When it is placed in contact with another conductor
When it is placed in contact with an insulator
When it is placed in contact with a superconductor
When it is placed in the magnetic field of another conductor
The two types of electromagnetic induction are:
Autoinduction and mutual induction
Self-induction and mutual induction
Generated induction and self-induction
Current induction and voltage induction
Self-induction is used in the operation of what device?
Step-up transformer
Autotransformer
Step-down transformer
Electronic timer
The strength of the magnetic fields in a transformer is increased by:
Coiling the wires and placing them in adjoining machines
Coiling the wires and letting their magnetic fields overlap
Keeping the wires very straight, increasing their effectiveness
Replacing the wires with diodes
Electricity is supplied to the imaging department by a:
Motor
Rectifier
Generator
Voltmeter
The electricity provided to the radiology department is
110 Hz or 220 Hz DC
110 Hz or 220 Hz DC
60 Hz AC
60 Hz DC
The electricity provided to the radiology department operates at
120 pulses per second
60 pulses per second
110 pulses per second
220 pulses per second
High-frequency power:
Is less effective than single-phase power
Has almost no ripple
Has more ripple than three-phase power
Is yet unproved
The primary advantage of three-phase power is that:
Voltage drops to zero only 6 times per second
Voltage drops to zero only 12 times per second
Voltage never drops to zero
Voltage is always at peak value
A variable transformer that is used to select kVp for the x-ray circuit is the:
Step-up transformer
. Autotransformer
Step-down transformer
Rectifier
A transformer that has more turns in the secondary coil than in the primary coil is called a:
Step-up transformer
Solenoid
Step-down transformer
Filament transformer
What is the transformer used to boost voltage to kilovoltage levels called?
Autotransformer
Step-down transformer
Step-up transformer
Low-voltage transformer
Voltage coming to the x-ray machine is kept constant through the use of a(n):
Autotransformer
Step-down transformer
Rectifier
Line voltage compensator
A step-down transformer:
Steps down voltage
Steps down current
Steps up voltage
Steps up resistance
Where does thermionic emission occur?
Step-down transformer
Rectifier
Cathode
Timer
Which of the following devices is prereading?
Step-down transformer
Rectifier
Timer
kVp meter
Which of the following are accurate?
A conductor allows the flow of electrons
The ampere is the unit of electromotive force
The volt is the unit of potential difference
The volt is the unit of electrical current
When performing filtration QC, the half-value layer (HVL) is used primarily to:
Measure focal spot size accurately
Indirectly evaluate total beam filtration and quality
Verify collimator alignment with the light field
Set the correct exposure index on the image receptor
A fluoroscopic image shows a random snowy appearance that is still visible when the x-ray beam is turned off. Which type of noise is present?
Quantum mottle
Scatter noise
Electronic noise
Veiling glare
A fluoroscopic unit equipped with ABS is measured at 12 R/min in normal fluoro mode. How should this be interpreted?
Acceptable for ABS units
Acceptable only in high-level control mode
Unacceptable; exceeds normal fluoro limits
Acceptable if SID is increased
Which activity BEST represents a Quality Assurance (QA) function rather than Quality Control (QC)?
Measuring HVL annually
Testing kVp accuracy
Reviewing repeat analysis trends and retraining staff
Evaluating focal spot size
If 400 mA, 10 ms, and 90 kV were used for a particular exposure using three-phase, 12-pulse equipment, which of the following exposure changes would be most appropriate for use on single-phase equipment to produce a similar image?
Use 200 mA
Use 20 mAs
Use 70 kV
Use 0.02 sec
Which generator is associated with an approximate 13% voltage ripple (87% actual voltage)?
High-frequency
Three-phase 6 pulse
Three-phase 12 pulse
Autotransformer
The protective housing is made of _______.
aluminum
tungsten
concrete
lead
The function of photocathode is converting
light photons into electrons
electrons into light photons
x-rays into electrons
electrons into x-rays
When measuring the accuracy of SID what is the variance that is allowed?
±2%
±5%
±10%
±3%
What is a scintillator?
Absorbs light and converts energy to x-rays
Absorbs light and converts to light
Absorbs x-rays and converts energy to light
Absorbs x-rays and converts to carbon
An exposure was made using 70 kVp @ 8 mAs. In order to maintain receptor exposure, what mAs value should be selected if the kVp is increased to 120?
4 mAs
2 mAs
16 mAs
24 mAs
