Reading...
Play button
Play button
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;
187 Cards in this Set
- Front
- Back
|
When were the first medical xrays done in the US?
|
3-4 months after discovery
|
|
|
Who was the first person to die of exposure to man-made radiation?
|
Clarence Dally
|
|
|
The cathode end of the tube carries a ________ electrical charge.
|
Negative
|
|
|
The source of the projectile electrons used in making xrays is the _________.
|
Filament
|
|
|
What is the type of radiation that is produced when a projectile electron passes near the nucleus of a target atom and sheds it's kinetic energy in the form of a photon?
|
Brehmsstruhlung
|
|
|
Who invented and refined fluoroscopy?
|
Thomas Edison
|
|
|
The anode end of the tube carries an overall _________ electrical charge.
|
Positive
|
|
|
Electrons have an overall __________ electrical charge.
|
Negative
|
|
|
The tungsten atom has only ___ electrons in its K Shell.
|
2
|
|
|
What are the two currents that pass through an xray tube?
|
Filament and the tube current
|
|
|
On the xray emission spectrum, the energy of the xray beam is measured in _____.
|
keV
|
|
|
The space charge produced when you rotor up an xray tube is limited in size. This limiting factor is known as __________.
|
Space charge effect
|
|
|
The area on the target where most of the projectile electrons strike the target anode is known as the __________.
|
Actual focal spot
|
|
|
True or false. Thermionic emission takes place on the anode target of the xray tube.
|
False
|
|
|
By placing an angle on the target anode, we can have a larger actual focal spot and still maintain a smaller effective focal spot. This is known as the ___________.
|
Line focus principle
|
|
|
The anode heel effect is a consequence of the ___________.
|
Line focus principle
|
|
|
What events must be completed before the exposure process can continue by pressing the second part of the exposure switch?
|
The space charge is formed by applying the filament current and the rotor is spinning at a high RPM
|
|
|
The heat units produced by a single-phase machine can be computed by which equation?
|
Hu = mAs x kVp
|
|
|
The controlling factor for beam quality is kVp. KVp is also a controlling factor for beam quantity because when kVp is increased then :
|
Target interaction efficiency increases at the anode
|
|
|
The US government states that all xray machines capable of 70 kVp or higher must have a total filtration of _______.
|
2.5 mm of aluminum or the equivalent
|
|
|
The process in which some xrays are transmitted and some are absorbed is called ___________.
|
Differential absorption
|
|
|
What is it called when the portion of the beam that isn't transmitted is either absorbed or scattered?
|
Attenuation
|
|
|
The type of scatter radiation that seldom exits the body is ________.
|
Photoelectric effect
|
|
|
The type of scatter radiation that is secondary radiation produced by an interaction between a photon and an inner shell electron is __________.
|
Photoelectric effect
|
|
|
If you are standing 2 feet from a patient that is being exposed to radiation and you step back 2 more feet so that you are 4 feet from the patient, how will this affect your exposure to the scatter radiation?
|
You will decrease your exposure by a factor of 4.
|
|
|
True or false. Photoelectric interactions are non-ionizing interactions and are not a risk to the patient.
|
False
|
|
|
If an orbiting electron moves into another shell closer to the nucleus, the result is ____________.
|
A characteristic photon
|
|
|
What is the type of radiation that is a risk to both the patient and anyone else in the proximity?
|
Compton's
|
|
|
The part of an intensification tube in which the light photons are converted to photoelectrons is known as ____________.
|
The photocathode
|
|
|
Define ionization of an atom.
|
The removal of an electron from an atom cfreating an ion with a positive charge.
|
|
|
The end of the image intensification tube that is closest to the patient is the ___________.
|
Cathode end
|
|
|
The part of the intensification tube that has a small 1" screen where the image is reproduced is called the _____________.
|
Output phosphor
|
|
|
True or false. Decreasing OID will increase detail.
|
True
|
|
|
What has the most detrimental effect on the detail of an image?
|
Motion
|
|
|
True or false. Increasing the SID will increase detail.
|
True
|
|
|
If you know that size of the image of an object and the magnification factor you can compute the actual size of the object with what equation?
|
object size=image size/MF
|
|
|
Geometric unsharpness is a result of the relationship between SID, OID and _________.
|
Focal spot size
|
|
|
True or false. All radiographs have some distortion because of the divergence of the beam.
|
True
|
|
|
What equation is used to measure the magnification of an object created by the OID?
|
MF = SID/OID
|
|
|
As SID increases, focal spot blur __________.
|
Decreases
|
|
|
What type of distortion occurs when the body part is not parallel to the IR?
|
Foreshortening
|
|
|
What type of distortion occurs when the body part is parallel to the IR and the tube is angled?
|
Elongation
|
|
|
How are grid ratios determined?
|
The height of the lead strips and the distance between them
|
|
|
The system used to automatically collimate the beam and lightfield to the cassette in a bucky tray is called _________________.
|
Positive beam limitation device
|
|
|
The bucky factor for a grid with a 12:1 ratio is ______.
|
5
|
|
|
Grids are employed when the body part thickness is greater than _________.
|
10 cm
|
|
|
True or false. A parallel grid used upside down will create grid cut-off.
|
False
|
|
|
When using an air gap technique, increasing the OID also will _______________.
|
Increase magnification and decrease detail
|
|
|
How is a focused grid different than a parallel grid?
|
The grid lines on a focused grid are angled to match the divergency of the beam.
|
|
|
What does DICOM stand for?
|
Digital imaging communication in medicine
|
|
|
The post processing technique that removes superimposed structures so that the anatomic area of interest is more visible is known as ____________.
|
Subtraction
|
|
|
What was the first imaging modality to become digital?
|
CT
|
|
|
True or false. A CRT monitor with 525 lines of resolution is well suited for viewing xrays.
|
False
|
|
|
Spectral matching of film and screen refers to the ___________.
|
Color of light that film is sensitive to and the color of light produced by the screen phosphors
|
|
|
Changing from a 400 speed screen to a 200 speed screen requires ________________.
|
An increase in mAs by a factor of two
|
|
|
Changin from a 400 speed screen to a 100 speed screen requires _____________.
|
An increase in mAs by a factor of four
|
|
|
If you made an exposure using 10 mAs with a 400 speed screen, what would your mAs be if you made that same exposure using a 100 speed screen?
|
40 mAs
|
|
|
What film/screen combination would require the highest mAs?
|
Slow speed detail screen or extremity
|
|
|
An artifact inside the cassette between the screen and the film will create ____________.
|
A light or white area on the film
|
|
|
True or false. The resolution created by good film to screen contact can be evaluated by doing a wire mesh screen test.
|
True
|
|
|
Using a detail cassette with the AEC unit will result in ___________.
|
The film being lighter that intended
|
|
|
When changing from a detail screen to a high speed screen, the mAs should be _____________.
|
reduced
|
|
|
Define spatial resolution.
|
The minimum separation between two objects at which they can be recognized.
|
|
|
The production of light during the stimulation of the phosphors is _________.
|
Fluorescence
|
|
|
The continuation of light emission after the stimulation of phosphors is _____________.
|
Phosphorescence
|
|
|
If a film comes out of the processor with a milky appearance over the image, the reason is most likely :
|
The clearing agent in the fixer is exhausted
|
|
|
True or false. An increase in density on films being run through a processor can be caused by the transport rollers running too fast.
|
False, running too slow
|
|
|
Inadequate washing of film during processing will result in the films ____________.
|
Having a brownish stain
|
|
|
The reducing agents in a processor are found in the ____________.
|
Developer
|
|
|
The purpose of the restrainer in the processor is to do what?
|
Prevent the unexposed crystals from being converted to metallic silver during developing.
|
|
|
What is superadditivity?
|
Two components that work better together than they do individually
|
|
|
Unexposed silver halide crystals are removed from the emulsion in the _________ tank.
|
Fixer
|
|
|
Stacking film boxes on one another can cause _________.
|
Static artifact
|
|
|
The active ingredient found in the fixer that halts the developing process is _________.
|
Acetic acid
|
|
|
Developer has what type of base?
|
Alkaline
|
|
|
True or false. The most common type of replenishment system found in processors used in busy hospitals is the flood replenishment.
|
False
|
|
|
If your films come out of the dryer most and tacky it is because ___________.
|
The hardener in the developer or fixer is exhausted
|
|
|
The time it takes for a processor to pass a film through from start to finish is refered to as _________.
|
the processor cycle
|
|
|
Define the half value layer
|
The amount of material required to reduce the xray beam to half its original value.
|
|
|
The type of scatter that is predominant about 75 kVp is __________.
|
Compton's scattering
|
|
|
The type of scatter radiation that is produced when an incident photon interacts with an outer shell electron, sheds enough energy to remove that electron from it's orbit and then continues on in a different direction minus the energy it lost during the interaction is ___________.
|
Compton's scattering
|
|
|
The natural filtration created by the glass and oil between the focal spot and the patient is _____________.
|
Inherent filtration
|
|
|
THe area on the target that is seen from viewing into the port of the tube and is angled to increase resolution is know as the ____________.
|
Effective focal spot
|
|
|
The current that is responsible for thermionic emission is the ___________.
|
Filament current
|
|
|
The current that is utilized to send the projectile electrons from cathode to anode is the ____________.
|
Tube current
|
|
|
In order to keep the projectile electrons in a small area before completing an exposure the focusing cup will exhibit a _________ charge.
|
Negative
|
|
|
By placing an angle on the target anode, we can have a larger actual focal spot and still maintain a smaller effective focal spot. This is also known as :
|
The line focus principle
|
|
|
Making a visible change in radiographic density requires that the minimum amount of change in mAs must be approximately __________.
|
30%
|
|
|
180 cm is the same as ____ inches.
|
72
|
|
|
The rectification number for computing heat units when operatin a three phase six pulse xray machine is ______.
|
1.35
|
|
|
The type of xray interaction that happens when a projectile electron collides with an inner K-Shell electron, dislodges it from its orbit, and a photon is produced when an outer shell electron falls into the void is called ___________.
|
Characteristic
|
|
|
The type of xray generator that turned the beam on and off 60 times per second is called ___________.
|
single phase
|
|
|
In order to produce characteristic radiation your kVp setting must be at least _______.
|
70
|
|
|
If your beam is 100% Bremsstruhlung radiation, that means that your kVp setting is no greater than ______.
|
69
|
|
|
What is the primary controlling factor for beam quantity?
|
mAs
|
|
|
True or false. Although mAs is the measurement of the quantity of photons produced during an exposure, increasing the kVp will also increase this quantity.
|
True
|
|
|
What are the three most important characteristics of a radiographic film?
|
Speed, contrast, and latitude
|
|
|
Most film cassettes should be replaced every how many years?
|
5-7
|
|
|
What are halide crystals mainly composed of?
|
Silver bromide
|
|
|
What type of atoms remain on the polyester base after processing that show up black on the xray?
|
silver
|
|
|
What is the substance that holds the silver halide crystals in place and allows processing chemicals to reach the crystals?
|
Gelatin
|
|
|
The distibution of exposed and unexposed crystals in the undeveloped film is called the __________.
|
Latent image
|
|
|
When exposed to radiation, the silver halide crystal releases electrons and silver ions. The ions travel to the sensitivity speck and create a greater positive charge there. Electrons are then attracted to the positive charge near the sensitivity speck, where they join with silver ions to become silver atoms. What is this called?
|
Gurney Mott Theory
|
|
|
What is the tiny imperfection in a silver halide crystal called?
|
Sensitivity speck
|
|
|
A wide latitude film provides a what type of contrast image?
|
Low
|
|
|
A film that uses very small silver halide crystals will have _______ detail.
|
Greater
|
|
|
The magnification factor is a product of _________.
|
SID/SOD
|
|
|
How is film speed determined?
|
By the size of the halide crystals and the concentration of them in the emulsion
|
|
|
True or false. Off level grid cut off is only a problem with focused grids and not parallel grids.
|
False
|
|
|
What type of grid uses two sets of lead lines that are set in opposite directions from each other?
|
Crosshatch
|
|
|
When collimation on a large body part is increased and the density of your image decreases because less scatter is produced, what is recommended in order to increase the density?
|
increase mAs
|
|
|
What is the grid conversion factor for a 12:1 ratio grid?
|
5
|
|
|
If a technique using an 8:1 grid was 36 mAs, what would the mAs be for a non-grid technique?
|
9
|
|
|
When changing from a detail screen to a high speed screen, that mAs should be ____________.
|
Reduced
|
|
|
Focal spot blur is increased when you change to a _______ focal spot.
|
Larger
|
|
|
True or false. Using a distance that is not within the recommended focal distance of a focused grid will produce grid cut off.
|
True
|
|
|
What type of grid has lead lines that run perpendicular to the plane of the film all across the grid?
|
Parallel
|
|
|
When the necessary radiation has been detected by an ionization chamber, the exposure is terminated at the __________.
|
Timer
|
|
|
True or false. If the entire back-up mAs is used during an exposure and the image is light in density, increasing the density control will supply the additional back up mAs to increase density.
|
False
|
|
|
The back-up mAs for any exam when using AEC should be no less than ___________.
|
150% of the anticipated amount of exposure
|
|
|
How many detectors are in an input screen of a fluoroscopic image intensifier?
|
1
|
|
|
If you are using the AEC and your image comes out too light even after increasing the density control, what should you do?
|
Reposition the patient so that the thickest body part is over the detector
|
|
|
If you cut your SID in half, you will need to decrease you mAs by how much in order to maintain density?
|
by a factor of 4
|
|
|
What is the purpose of a focusing cup?
|
To keep the space charge intact by exhibiting a negative charge
|
|
|
What formula is used to determine change needed in mAs when SID is changed in order to maintain density?
|
New mAs =old mAs(d2/d1)squared
|
|
|
The type of target interaction that involves a projectile electron passing through the electron field surrounding a target atom and interacting with the nucleus of the atom is called ____________.
|
Brehmsstruhlung
|
|
|
What is the reciprocity law?
|
It states that the density produced on an x-ray will be equal for any combination of mA and time as long as the product of the mAs is equal
|
|
|
What type of x-ray interaction absorbs the incoming photon and is a major element in differential absorption?
|
Photoelectric
|
|
|
What type of scatter radiation seldom exits the patient but is still a concern for the tech because it can produce biological changes in the patient?
|
Photoelectric
|
|
|
True or false. X-rays are produced isotropically.
|
True
|
|
|
What should the amount of total filtration be?
|
2.5 mm of aluminum or equivalent
|
|
|
What is equivalent to increasing the kVp by 15%
|
doubling the mAs
|
|
|
What is added filtration?
|
The filtration added to the unit to complete the necessary 2.5 mm equivalent needed to be compliant with federal law.
|
|
|
The area on the target where most of the projectile electrons strike the target anode is the ___________.
|
Actual focal spot
|
|
|
What are the external electromagnets called that control the spinnin of the anode of an x-ray tube?
|
the stator
|
|
|
The shaft and rotor are part of what end of the tube?
|
Anode
|
|
|
The type of xray interaction that happens when a projectile electron collides with K-Shell electron and dislodges it from its orbit is _________.
|
Characteristic
|
|
|
The type of xray interaction that never varies in energy levels is __________.
|
Characteristic
|
|
|
What is the grid conversion factor for a 5:1 grid?
|
2
|
|
|
True or false. Placing an angle on the target in order to increase resolution by reducing the size of the effective focal spot is known as the anode heel effect.
|
False
|
|
|
What happens when filtration is added to the x-ray beam?
|
The overall average energy of the beam increases
|
|
|
What interaction occurs when a projectile electron interacts with an inner shell electron of a target atom and that electron is removed from orbit, a photon is produced when an outer shell electron advances towards the nucleus to fill that void?
|
A characteristic interaction
|
|
|
True or false. Short scale contrast can be achieved by using high kVp settings and long scale contrast can be achieved by using low kVp settings.
|
False
|
|
|
True or false. Most diagnostic xray tubes will use stationary anodes.
|
False
|
|
|
What steps processing are considered archiving steps?
|
Washing & drying
|
|
|
What does reduction do during processing?
|
Process of gaining electrons in order to change it.
|
|
|
What is oxidation?
|
Giving up electrons in order to change it
|
|
|
What are the developer reducing agents?
|
Phenidone and Hydroquinone
|
|
|
What happens during processing when the reducing agents are introduced?
|
Silver ions are turned into atoms
|
|
|
What is the purpose of the restrainer during processing?
|
To decrease the reduction or development of unexposed silver halide, prevents fogging
|
|
|
What prevents light from bouncing back on a single emulsion film?
|
Antihalation layer
|
|
|
High speed film has what type of latitude and contrast?
|
Narrow or short latitude and high contrast
|
|
|
What formula is used when determining technique when cassette speeds are changed?
|
mAs1/mAs2=Speed2/Speed1
|
|
|
What is the formula for finding heat units?
|
HU= mAs x kVp x generator factor
|
|
|
What is the generating factor for a single phase generator?
|
1
|
|
|
what is the generating factor for a 3 phase 12 pulse generator?
|
1.41
|
|
|
What is the generating factor for a high frequency generator?
|
1.45
|
|
|
What is the big difference between characteristic x-rays and the photoelectric effect?
|
With characteristic x-rays, a projectile electron ejects the inner K-shell electron while with the photoelectric effect; the inner K-shell electron is ejected by an x-ray photon.
|
|
|
The probability of total photon absorption during the photoelectric effect is dependent on what?
|
The energy of the incoming x-ray photon and the composition of the anatomic tissue.
|
|
|
What is transmission?
|
When an incoming x-ray photon passes through the anatomic part without any interaction with the anatomic structures
|
|
|
What is the 15% rule?
|
If you change the kVp by 15% it will have the same effect on density as doubling the mAs or reducing the mAs by 50%
|
|
|
What is the definition of the inverse square law?
|
States that the intensity of the beam is inversely proportional to the square of the distance from the source.
|
|
|
What is the formula for the inverse square law?
|
New intensity or mAs = old intensity (d1/d2)squared
|
|
|
What is the density maintenance formula?
|
New mAs = old mAs (d2/d1)squared
|
|
|
What is the conversion factor for a 5:1 grid?
|
2
|
|
|
what is the conversion factor for a 6:1 grid?
|
3
|
|
|
What is the conversion factor for an 8:1 grid?
|
4
|
|
|
What is the conversion factor for a 12:1 grid?
|
5
|
|
|
What is the formula for changing or adding/removing a grid?
|
mAs1/mAs2 = conversion factor1/conversion factor2
|
|
|
The higher the grid ratio, the __________ technique is needed.
|
higher
|
|
|
What is the formula for changing film screen speed?
|
mAs1/mAs2 = RS2/RS1
(RS=relative speed) |
|
|
How does increasing collimation (making the field size smaller) impact density?
|
Decreases density
|
|
|
At what point do US public law require that generators automatically terminate AEC exposures?
|
At 600 mAs or 60 kW seconds above 50 kVp and 2000 mAs below 50 kVp
|
|
|
What is the most common grid ratio used?
|
10:1 or 12:1
|
|
|
True or false. Quantum mottle can be caused by grid cut off.
|
True
|
|
|
How does off focused grid cutoff occur?
|
When using an SID outside of the recommended focal range. This will only occur when using a focused grid or with a parallel grid at very short SID.
|
|
|
How does off center grid cut off occur?
|
When the CR is not aligned from side to side with the center of a focused grid.
|
|
|
How does off level grid cut off occur?
|
When the CR is not perpendicular with the grid
|
|
|
What is the purpose of using grids?
|
To improve contrast
|
|
|
What type of grid has grid lines that are angled to match the angle of divergent rays?
|
Focused grid
|
|
|
True or false. Witha parallel grid, there will always be some grid cut off?
|
True, due to the lead lines not being angled to include divergent rays
|
|
|
What processing errors can increase density?
|
High temp, over-replenished developer, light leak, slow roller speed
|
|
|
What processing errors can decrease density?
|
Exhausted developer, low developer temp, rollers moving too fast
|
|
|
What can cause the xray to have a pinkish stain after processing?
|
Contamination of chemicals or under replenishment
|
|
|
What can cause the film to have the emulsion removed during processing?
|
insufficient hardener in developer
|
|
|
What will storing film at higher temp do to the film?
|
fogging
|
|
|
How can humidity during film storage have an impact on the film?
|
fungus from high and static from low humidity
|
