What does ALARA mean?

as low as reasonably achievable

inhibit movement of electrical charge

A transformer with more secondary windings than primary windings

has a greater secondary voltage

A generator is a device that converts

mechanical energy to electrical energy

A series circuit has three resistors with values of 8, 12, and 15 ohms. If the voltage is 110V, what is the voltage across each resistor?

R1 = 25V R2 = 37.68V R3 = 47.1V

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Ch 1,2,3,4 EO

EO Review for final

Question	Answer
Electrification occurs through the movement of _____.	electrons only
The charges on an electrified object are distributed ____.	evenly throughout the object
The maximum number of electrons that can exist in an electron shell is calculated with the formula _____.	2n2
An atom that loses or gains one or more electrons is a(n) _____.	ion
The binding energies, or energy levels, of electrons are represented by their ____.	shells
Electrical power is measured in _____.	watts
A series circuit has three resistors with values of 8, 12, and 15 ohms. If the voltage is 110V what is the total resistance?	35 Ohms
What does ALARA mean?	as low as reasonably achievable
If the distance between two electrical charges is doubled, the force between them is	decreased by 1/4
The energy of x-rays is _____.	electromagnetic
The magnetic intensity of an electromagnet is greatly increased by the addition of a(n) _____ core.	iron
A ______ is a source of direct current.	battery
When a group of dipoles are aligned, they create _____.	a magnetic domain
The _____ of electromagnetic radiation is constant.	velocity
Electric insulators	inhibit movement of electrical charge
The rotation of electrons on their axis is the property called _____.	electron spin
What are the fundamental particles of an atom?	proton, electron, neutron
Rubber and glass are ______.	insulators
A parallel circuit has three resistors with values of 14, 18, and 27 ohms. If the voltage is 220V what is the total resistance?	6.1 Ohms
What is Ohm's Law?	I = V/R
Electrification occurs through the movement of _____.	electrons only
A transformer with more secondary windings than primary windings	has a greater secondary voltage
The innermost electron shell is symbolized by the letter _______.	K
Gamma rays are produced in the ______ of the atom.	nucleus
The atomic number of an element is symbolized by the letter ____.	Z
What would the output voltage be if the primary voltage is 220. The primary has 250 windings and the secondary has 275 windings.	242V
What is the unit of electric potential?	volt
Radio waves, light, and x-rays are all examples of ______ energy.	electromagnetic
A current of 2 amperes and a resistance of 8 ohms require what voltage in a series circuit?	16 volts
A generator is a device that converts	mechanical energy to electrical energy
Ohm's law is mathematically described as	R = V/I
A neutral atom has the same number of ______ and electrons.	protons
Atoms and molecules are the fundamental building blocks of ____.	matter
When an atom has the same number of protons as another, but a different number of neutrons, it is called an ______.	isotope
It = I1 + I2 + I3 + In	parallel circuit
V = I x R	Ohm's law
10V + 5V + 12V + 3V = 30V	series circuit
6.24 x 10 to the 18th electrons / sec	ampere
Material that allows heat or electric current to flow	conductor
SI unit for potential difference	Volt
The distance between similar points on a sine wave: the length of one cycle	wavelength
Number of cycles or wavelengths of a simple harmonic motion per unit of time. Expressed in Hertz. 1 Hz = 1 cycle/s	frequency
Like magnetic poles _____ and unlike magnetic poles _____.	repel, attract
What is the removal of an electron from an atom called?	ionization
A series circuit has three resistors with values of 8, 12, and 15 ohms. If the voltage is 110V, what is the voltage across each resistor?	R1 = 25V R2 = 37.68V R3 = 47.1V
Exposure is measured in units of ______.	grays
Primary windings is equal to 5,000 and the secondary windings equals 100. What would the output amperage be if the input amperage is 2?	100 Amps
Ionizing radiation is capable of removing ____ from atoms as it passes through the matter.	electrons
What is the electromagnetic wave equation?
If 20V of potential difference causes a current of 5 amperes to flow in a parallel circuit, the resistance produced is	4 ohms
A stator consists of	electromagnets
The lowest energy range of the electromagnetic spectrum is _____.	radio waves
The milliampere(mA) is a unit of	current
A charged particle in motion creates a(n) ______.	magnetic field
What type of material can be made magnetic when placed in an external magnetic field?	ferromagnetic
An alternating (AC) current is represented by a _______ line.	sinusoidal
An atom in a normal state has an electrical charge of _____.	zero
A motor is a device that converts	electrical energy into mechanical energy
Filtration is used to ______	absorb low-energy x-rays
The smallest unit of electrical charge is the _____.	electron
The unit of electrical power is	watt
The reduction of radiation intensity due to scattering and absorption is called ______.	attenuation
A parallel circuit has three resistors with values of 14, 18, and 27 ohms. If the voltage is 220V, what is the total current?	36 Amps
On the surface of an electrified object, the charges concentrate on the ______.	sharpest curvatures
What is the unit of electric potential?	volt
A moving object has _____ energy.	kinetic
The only difference between x-rays and gamma rays is their _____.	origin
Photons with the highest frequencies have the _____.	shortest wavelengths
A positively charged nucleus surrounded by negatively charged electrons in well-defined orbits is the _____ model of the atom.	Bohr
When a group of dipoles are aligned, they create _____.	a magnetic domain
A parallel circuit has three resistors with values 8, 12, and 15 ohms. If the voltage is 110V what is the current through each resistor?	13.75 Amps 9.2 Amps 7.3 Amps
The energy of a photon is directly proportional to its _______.	frequency
Primary windings is equal to 100 and the secondary windings is equal to 65,000. What would the output voltage be if the primary voltage is 50?	32,500 Volts
Primary windings is equal to 5,000 and the secondary windings equals 100. What would the output amperage be if the input amperage is 2?	100 Amp
Full-wave rectified, three-phase units provide an x-ray beam at ___ pulse(s) per second.	360
An increase of 15% in kVp is equivalent to increasing mAs ___.	100%
A diode allows electrons to flow from _____.	cathode to anode
The _____ is/are outside the glass envelope.	Stators
The target of the rotating anode is usually coated with a _____ alloy.	tungsten
A single-phase waveform has ____ ripple.	100%
In modern imaging systems, the components for rectification are _____.	solid state semiconductors
Bremsstrahlung x-rays are produced by ____ at the target.	slowing electrons
The most accurate type of timer is the ____ timer.	electronic
What would the output voltage be if the primary voltage is 220. The primary has 250 windings and the secondary has 275 windings.	242 Volts
The ______ is the source of radiation in the x-ray tube.	focal spot
Because of the line focus principle, the effective focal spot size decreases with decreasing _____.	target angle
Changes in _____ result in directly proportional changes in the amplitude of the emission spectrum.	both mA and time
An increase in mAs would _____ the ____ of the emission spectrum.	increase, amplitude alone
If an exposure is 0.5 mGya at an SID of 40 inches, what would the exposure be at an SID of 60 inches?	0.222 mGya (because of the inverse square law)
If the distance from the source to the image (SID) is reduced by half, how is the x-ray intensity at the image affected?	Intensity increases 4 times because of the inverse square law
A low quality beam would also have low ______.	penetrability
The _____ circuit provides electrons for the x-ray tube current.	filament
Characteristic x-rays are produced by ____.	released binding energy
How does added filtration affect the emission spectrum?	Added filtration causes reduced amplitude and a shift to the right on the emission spectrum.
The filament is made of ______.	tungsten
The amplitude of the emission spectrum with a ____ generator is ____ it is with a three-phase generator.	single-phase, lower than
Variations in power distribution to the x-ray machine are corrected by the _____.	line voltage compensator
A step-down transformer is located in the _____ circuit.	filament
When electrons bombard the target, ____% of their kinetic energy is converted to heat.	99
The rotating anode is turned by a _____.	magnetic field
During an exposure, most of the ____ energy of the projectile electrons is converted to _____.	kinetic, heat
The negative side of the x-ray tube holds the ______.	filament
Most of the x-rays produced at the target are ____.	bremsstrahlung
Added filtration will _____ beam quality and ____ quantity.	increases, decreases
X-ray beam quality is improved by _____.	increasing filtration
A 15% increase in kVp is equivalent to _____.	doubling the mAs
Beam quality is affected by _____.	kVp and filtration
The x-ray intensity is lower on the anode side of the tube because of the _____.	heel effect
An x-ray beam that could pass through dense tissue would have high _____.	quality and penetrability
Three main parts of the x-ray imaging system are the x-ray tube, ____, and _____.	operating console, and high voltage generator
The half value layer (HVL) of an x-ray beam is a measurement of beam _____.	quality
The quantity of bremsstrahlung radiation increases proportionally with increased _____.	mAs
Electron interactions at the inner-shell of the target atoms produce _____ radiation.	characteristic
An exposure taken at 100 kVp would have a continuous emission spectrum with a maximum energy of ____ keV.	100
Approximately ______ of the kinetic energy of the projectile electrons is converted to x-rays at the target.	1%
At 55 kVp, _____ of the x-rays produced are bremsstrahlung.	100%
The difference in the waveform between the primary and secondary sides of the high voltage transformer is _____.	amplitude
Projectile electrons travel from ______.	cathode to anode
Thermionic emission at the filament creates a _____.	space charge
The operating console contains circuits that are _____.	low voltage
The discrete portion of the x-ray emission spectrum would change position with a change in _____.	target material
An increase in kVp would _____ the _____ of the emission spectrum.	increase, position alone
The most widely used support structure for the x-ray tube is the ____.	ceiling support system
The first component to receive power in the x-ray circuit is the ____.	autotransformer
Voltage across the x-ray tube is most constant with _____.	high frequency generators
At the target, the projectile electrons interact with _____.	both outer and inner shell electrons in the target
The number of x-rays in the useful beam defines x-ray _____.	quantity
The penetrability of an x-ray beam is called x-ray _____.	quality
The effective focal spot size is _____ the actual focal spot size.	smaller than
X-ray quantity increases in direct proportion to increases in ___.	mAs
With half-wave rectification, the current flows through the x-ray tube during the ____ part of the cycle.	positive
If the intensity of a 70 kVp exposure at 20 mAs is 1.0 mGya, what would it be at 5 mAs?	0.25 mGya (exposure is proportional to mAs)
The main purpose of added filtration is to reduce _____.	patient dose
Differential absorption is primarily caused by	photoelectric effect
Subject contrast is affected by ______.	patient thickness
The input phosphor converts ____ to _____.	x-rays, light
Digital fluoroscopy with a charge-coupled device has lower _____ and higher ______ than conventional fluoroscopy.	patient dose, light sensitivity
K-shell binding energy increases with increasing _____.	atomic number
Differential absorption is dependent on the _____.	mass density and atomic number of the absorber, and kVp of the exposure (all of the above)
Brightness gain is typically in the range of ______.	5,000-30,000
The _____ is the product of the minification gain and the flux gain.	brightness gain
A charge-coupled device used in digital fluoroscopy provides high _____.	spatial resolution, signal-to-noise ratio, detective quantum efficiency (all of the above)
At energies below 40 keV, the predominant x-ray interaction in soft tissue and bone is _____.	photoelectric absorption
An image intensifier tube is identified by the diameter of its ____.	input phosphor
The _____ in the image intensifier emits electrons when it is stimulated by light photons.	photocathode
Digital fluoroscopic dose rate is lower than that for continuous analog fluoroscopy.	True
X-rays transmitted without interaction contribute to _____.	the radiographic image
Compton scatter is directed at ____ angle from the incident beam.	any
In _____, there is complete absorption of the incident x-ray photon.	photoelectric interaction
A negative contrast agent is _____.	air
The use of contrast agents increases the amount of _____.	Compton scatter, differential absorption, photoelectric absorption (all of the above)
The best way to minimize magnification is to use a _______.	long SID, small OID (both A and B)
Only energies above 10 MeV can ______ take place.	photodisintegration
Radiographic image quality is improved when the ____ is increased.	source image distance
As kVp _____, the probability of photoelectric absorption _____.	increases, decreases
Fluoroscopy for air contrast barium enema is generally done at ____ kVp.	80-90
An outer-shell electron is ejected and the atom is ionized during _____.	Compton interactions
If 5% of an incident beam is transmitted through a body part, then 95% of that beam was ______.	attenuated
Which x-ray interaction involves the ejection of the K-shell electron?	photoelectric absorption
The combination of temporal and energy subtraction techniques is called _____.	hybrid subtraction
The ratio of x-rays incident on the input phosphor to light photons exiting the output phosphor is called ____ gain.	flux
The number of light photons emitted within the image intensifier is _____ to the amount of x-ray photons exiting the patient.	directly proportional
When the mass density of the absorber is ____, it results in ____ Compton scatter.	increased, increased
Light produced at the output phosphor of the image intensifier has been increased _____ times in intensity.	50-75
Which of these body parts has the highest subject contrast?	chest
The kinetic energy of photoelectrons in the image intensifier is greatly increased by the ______.	potential difference across the tube
Differential absorption is the result of differences between:	Photoelectric effect and transmission
The output phosphor of the image intensifier is composed of ___.	zinc cadmium sulfide
Fluoroscopy was developed so that radiologists could view ____ images.	dynamic
Digital fluoroscopy uses at least _____ monitor(s).	2
The image intensifier improved fluoroscopy by increasing image _____.	brightness
What has the greatest mass density?	bone
Attenuation is caused by ______.	absorption and scattering (both A and B)
An incident x-ray interacts with an atom without ionization during ______.	coherent scattering
Barium is a good contrast agent because of its _____.	high atomic number
What is the milliamperage used during fluoroscopy?	less than 5 mA
Viewing the fluoroscopic image in magnification mode increases _____.	spatial and contrast resolution, patient dose (all of the above)
The capability of an image intensifier to increase the illumination level of the image is called its ______.	brightness gain
______ occurs only at the very high energies used in radiation therapy and in nuclear medicine P.E.T. imaging	Pair production
Anatomic structures that readily transmit x-rays are called:	radiolucent
X-rays that exit the patient and enter the image intensifier first interact with the ______.	input phosphor
The two primary forms of x-ray interaction in the diagnostic range are ______.	Compton scattering and photoelectric absorption
In digital radiography, the latent image is formed on the _____.	detector
In digital radiography, spatial resolution is improved with increased _____.	matrix size
The computed radiography cassettes is called a(n) _____ plate.	imaging plate
Digital radiography images should be repeated if there is a problem with ____.	none of the above
The computed radiography image has ____.	wide exposure latitude and improved contrast resolution
PACS stands for:	Picture Archiving and Communication System
The portion of useful image-forming x-rays is referred to as the ____.	signal
Image detail is also called ______.	spatial resolution
If an image receptor has a high probability of interacting with the x-ray beam, then it has a high _____.	DQE
The four steps of creating an image with computed radiography are ____.	metastable, read, stimulate, and erase
A digital display device with higher megapixels has better spatial resolution. T/F	true
The human visual system can distinguish ____ shades of gray.	30
The national standard for image transmission in teleradiology is the ____ format.	DICOM
What is the most recent development in digital radiography image receptors?	direct capture solid-state devices
Spatial frequency is used to describe the quality of spatial resolution in terms of ____.	Lp/mm
CR systems acquire clinical information by:	laser scanning a PSP plate
The photostimulable phosphor screen is handled in a _____.	reader
Computed radiography is also referred to as:	PSP technology
Computed radiography imaging produces ____ gray levels	10,000
DQE is ____.	Detective Quantum Efficiency
As mAs is increased the signal to noise ratio is _____.	increased
With digital imaging, patient dose can be reduced by using higher ____ techniques.	kVp
The laser beam must be less than 100 nm in diameter in order to maintain _____.	high spatial resolution
A common feature between indirect and direct DR technology is:	thin film technology (TFT)
Computed radiography screens responds to radiation with ____.	Photostimulable luminescence
Indirect DR uses ____ as the detector material.	amorphous silicon
If there were such a thing as a perfect imaging system, the MTF would be equal to ____.	1
In digital imaging, spatial resolution is ultimately limited by ____.	pixel size
When the quality of a digital detector is inspected for purchase, the preferred detector for purchase would have a:	68% DQE 0.80 MTF
The science of ___ is the study of the response of the human eye to light.	photometry
With computed radiography the contrast is ____.	constant, regardless of radiation exposure
____ is prevented by flooding the erased imaging plate with bright light.	ghosting
Computed radiography developed in the 1970s with the use of ____ as the image receptor.	phosphor
The number of gray shades that an imaging system can reproduce is called its ____.	dynamic range
Switching from screen-film imaging to computed radiography can ____ patient dose.	reduce
Which of the following describes the ability of the imaging system to resolve fine details present in an object?	spatial resolution
Europium is the _____ of the photostimulable phosphor.	activator
Conventional x-ray tubes and cassettes are used with ____ radiography systems.	computed
The layer of a flat-panel indirect capture detector include:	scintillator, photodiode, TFT array
High capacity tube rotors revolve at ____ rpm.	10,000

Created by: Kdobson

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