Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
73 Cards in this Set
- Front
- Back
In many cases, digital fluoroscopy eliminates which of the following?
|
Postprocedure "overhead" films
|
|
A photostimulable phosphor is the active component of what piece of equipment?
|
Computed radiography imaging plate
|
|
In computed radiography, the image plate must be turned into digital form by what device?
|
Analog-to-digital converter
|
|
A mathematical formula used to reconstruct 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 colums known as:
|
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 outer 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
|
|
Elextromagnetic radiation travels:
|
In waves along a straight path
|
|
Electromagnetic radiation travels in bundles of energy called:
|
Photons
|
|
X-rays travels at what speed?
|
The speed of light, 186,000 miles per second
|
|
Waves of radiation are called:
|
sine waves
|
|
Wavelenght 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 x-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 the 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 describes:
|
Inverse square law
|
|
As radiation strikes matter:
|
The energy is transferred to the atoms according to the law of conservation of energy
|
|
Which statements are true regarding electrostatic charges?
|
Electrostatics is the study of electric charges at rest; Electrostatic charges concentrate on a conductor in the area of the greatest curvature.
|
|
Which statements are false?
|
The volt is the unit of electric current; The ampere is the unit of eletromotive force; Ohm'law is calculated using the equation VI=R
|
|
Electromagnetic induction is the process of causing an electric 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?
|
autotranformer
|
|
The strength of the magnetic fields in a transformer is increased by:
|
coiling the wires 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 radiology 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 xray circuit is the:
|
autotransformer
|
|
A transformer that has more turns in the seconday than in the primary coil is called a?
|
step-up transformer
|
|
The transformer used to boost voltage to kilovoltage levels is called a?
|
Step-up transformer
|
|
Voltage coming to the xray machine is kept constant through the use of a:
|
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 chagred focusing cup?
|
filament
|
|
What is composed of solid-state, silicon-based diodes?
|
Rectifier
|
|
What regulates the duration of xray production?
|
Timer
|
|
What is located in the xray circuit between the high-voltage transformer and the xray tube?
|
rectifier
|
|
What measures tube current?
|
mA meter
|
|
What device spins at 3300 to 10,00 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 shorest 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 IR?
|
Ionization chamber
|
|
The filament is kept warm by:
|
A standby current from the time the xray machine is turned on.
|
|
Activating the rotor will?
|
Reduce tube life
|
|
When making an exposure, the radiographer should:
|
Activate the rotor and the exposure switch in 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 xray tube.
|
Current
|
|
Heat is produced in the xray tube as:
|
Electrons interect with the target material
|
|
Most of the energy conversion in the xray tube produces:
|
Heat
|
|
Xrays are produced as incident electrons interect with target atoms by a process called:
|
Bremsstrahlung
|
|
Xrays are produced as incident electrons interact with inner shell electrons in target atoms by a process called:
|
Characteristic
|
|
What percentage of energy in the xray tube is converted to xrays?
|
1%
|
|
Which are properties of xrays?
|
Affect film emulsion; Scatter and produce secondary radiation; Invisible to the human eye; Travel in bundles of energy called photons; can ionize matter and gases; Cause phosphors to fluoresce.
|
|
The xray beam is:
|
Heterogeneous or polyenergetic, consisting of many different energies(wavelengths).
|
|
The xray 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
|
|
Which statements regarding filtration is true?
|
Total filtration (not less than 2.5 aluminum equivalent) = inherent filtration(glass envelope,tube housing, oil) + added filtration (aluminum).
|
|
Calculating heat units for three-phase, twelve-pulse equipment 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 tyoe of equipment.
|