Prelims Flashcards
it allows a facility with limited resources and personnel to monitor the basic components of the imaging process at a low cost through the use of simple, inexpensive tools and minimal staff time
quality control
it is a program designed by management to assure quality of a product or service
quality assurance
it involves specific actions designed to keep measurable aspects of the process involved in manufacturing a product or providing a service within specified limits
quality control
All medical facilities using x-ray equipment, from a simple intraoral dental unit to an image intensified special procedures system, will benefit from adopting a ________ ______
quality assurance
It is essential that one person at a given facility, the ______ _________, be in charge of maintaining the QA program and be allotted the time, equipment, and space necessary to carry out the duties that are required
QA coordinator
the facility’s __ _________ may choose to assign specific duties to other personnel but should maintain oversight and realize that consistency is compromised when several people share the responsibility of carrying out these tasks
QA coordinator
they must ensure all the tasks are performed in a timely manner regardless of assigned staff availability
QA coordinator
daily tests should take about __ minutes to perform and should be done prior to the first patient image of the day
5 minutes
monthly tests will add an additional __ minutes to the daily tests
10 minutes
quarterly tests will take about __ minutes to perform
45 minutes
the semiannual test for darkroom fog should take no more than _ minutes to perform and analyze
5 minutes
the annual tests will probably take _ to _ hours to perform
1 to 2 hours
its objective is to assure that the anode and other components of the x-ray machine do not experience shock and stress due to a sudden and excessive head load, which would shorten the useful life of the x-ray tube
x-ray tube warm up
its objective is to determine if the processor is working optimally
processor QC (sensitometer)
its objective is to keep the darkroom clean and processing optimized
daily and weekly darkroom QC
its objective is to assure the radiographic system is operating consistently
system constancy test
its objective is to assure that all components of the radiographic x-ray system indicator lights, displays and mechanical locks and detents are working properly and that the mechanical rigidity and stability of the equipment is optimum
radiographic system visual checklist
its objective is to ensure viewboxes are clean and light levels are kept consistent throughout
viewboxes
its objective is to identify ways to minimize patient exposure and reduce costs by addressing higher than normal repeat rates
repeat analysis
its objective is to assure film and chemistry quality is maintained and inventory is rotated on a first in, first out basis
film and chemical storage
its objective is to identify and minimize artifacts that may obscure clinical findings on the radiographs
artifact evaluation
its objective is to assure that screens and cassettes are free of dust and dirt particles that may degrade image quality
intensifying screen cleaning procedure
its objective is to determine and minimize the amount of darkroom fog
darkroom integrity/fog test
darkroom integrity also called as __ ______
fog test
its objective is to assure that optimum contact is maintained between the screen and film in each cassette
screen film contact test
its objective is to assure that the light field accurately defines the x-ray field
collimation tests
its objective is to assure that the source to image distance is indicated accurately
source to image distance indication
its objective is to assure that the positive beam limitation device or automatic collimation system is operating properly
automatic collimation accuracy
its objective is to assure that the lead aprons, gloves, gonadal shield and thyroid collars provide optimal protection when positioned appropriately
lead apron, glove, gonadal and thyroid shield integrity check
its objective is to assure that the fluoroscopic unit is functioning properly
fluoroscopy image quality check
its objective is to assure that the fluoroscopic unit is functioning properly
fluoroscopic system high contrast resolution and patient exposure
its objective is to assure that the fluoroscopic unit is functioning properly
fluoroscopy system visual checklist
it is objective is to assure the audible indicator for the high level control (HLC) is functioning properly, if HLC is available
fluoroscopic high level control test
it is reprinted from the 1998 ACR Barium Enema Quality Control Manual with permission of the American College of Radiology, Reston, Virginia
processor quality control
5 required equipment for processor quality control
sensitometer
densitometer
box
control chart
non mercury thermometer
a protective covering of gelatin that enclosed the emulsion
topcoat/protective coating
topcoat is made up of _______
gelatin
its purpose is to prevent damage to sensitive emulsion layer
it protects the emulsion from scratches, pressure and contamination
topcoat/protective coating
it is the heart of the radiographic film and it is the active layer
emulsion
size of emulsion
3-5 μm
emulsion is made up of _____ and ______
silver halide crystal and gelatin
it is the recording medium and is the active ingredient of the emulsion
silver halide crystal
size of silver halide crystal
1 to 1.5 μm
it is the mechanical binder that holds the silver halide crystal uniformly dispersed in place
it is clear and sufficiently porous
gelatin
a thin coating located between the emulsion and base that simply adheres the base to the emulsion
adhesive layer
it allows emulsion and base to maintain proper contact and integrity
adhesive layer
it is the foundation or framework of the film and it is composed of polyester
base
size of polyester
150 to 300 μm
it purpose is to provide a rigid structure onto which the emulsion can be coated
base
characteristics of a good film base:
lucency
dimensional stability
superior physical stability
blue tint
3 characteristics of x-ray film
film speed
film latitude
film contrast
spectral sensitivity
it is the speed point and is the degree to which the emulsion is sensitive to x-rays or to light
film speed
two primary factors that affect the speed point:
the number of SHC
the size of SHC
it is the margin of errors in technical factors that the film allows that will still produce an acceptable range of densities
film latitude
it is the inherent characteristics of the film emulsion that allows a moderate or acceptable range of densities to be recorded
film latitude
it is the inherent ability to record minute differences in densities across the film ability of the radiographic film to provide a certain level of image contrast
film contrast
3 types of spectral sensitivity
monochromatic
orthochromatic
panchromatic
3 general types of x-ray film
screen type film
direct exposure film
single emulsion film
it occurs when light forms an angle affecting a spot in the emulsion and travels through the other side striking a spot not exactly corresponding to the opposite layer, producing an effect similar to penumbra
parallax effect
the most widely used radiographic film, general choice for diagnostic radiology and is made to be used
screen type film
it is a film designed for use without the need of an IS, also erroneously called a non-screen film
direct exposure film
it has emulsion coated on one side of the base only, no parallax effect
single emulsion film
blue sensitive
sensitive to wavelength <550nm
globular grains
calcium tungstate phosphor
insensitive to red, orange and yellow
monochromatic film
green sensitive
sensitive to wavelength <620nm
tabular grains
rare earth phosphor
insensitive to red
orthochromatic film
sensitive to all visible light
mainly used in photography
sensitive to all visible light spectrum
no insensitivty
panchromatic film
4 layers of Intensifying Screen
base
reflective layer
phosphor layer
protective coating
it is layer of IS that provides support to the phosphor layer that is made of high grade cardboard, plastic or polyester
base
it is layer of IS that serves to redirect light toward the film and intercepts light photons headed in other direction and redirects them to the film
reflective layer
it is layer of IS that active and most important layer of intensifying screen that emits light during stimulation by x-ray and is made up of binder and phosphor crystals
phosphor layer
ability to give off visible light
luminescence
ability of phosphor to give off light only while exposed to x-ray, important to radiography
fluorescence
it is ability of phosphor that continue to emit light even after x-ray exposure has ceased or stopped, produces afterglow or screen lag, important to fluoroscopy
phosphorescence
the ability of the phosphor to interact with x-ray
detective quantum efficiency
the ability of the phosphor to convert x-ray into light
conversion efficiency
specific color that the phosphors emit must match with the spectral sensitivity of the film
spectral matching
it is insignificant in radiography but is used in fluoroscopy
minimum afterglow/lag
it is layer of IS that gives physical protection to the delicate phosphor layer that provides a surface which can be handled and cleaned without damaging the phosphor
it also prevents static build-up
protective coating
_________ is the rigid, light-tight container that holds the screens and film in close contact
cassettes
metal frame with low Z and radiolucent front
composed of magnesium, bakelite or carbon fiber
cassette front
compression device or compression layer that maintains proper film screen contact
contact felt
light-tight seal is completed by a snap or latch hinges
black felt is used in older styles
hinges
4 layers of cassette
cassette front
contact felt
hinges
cassette back
test for screen fim contact
wire mesh test
transitory poor screen film contact, more obvious in the serial changing film cassette, a curved back or curved front cassette will prevent ____ ______
air trapping
size of darkroom
15 ft x 9.5 ft or greater
darkroom can be adjacent to exposure room only if the walls is:
concrete
hollow blocks
wood
it is use to give enough visibility to accomplish necessary duties in handling the processing of x-ray film without harmful effect to the unprocessed film
safelight
distance of safelight
3 to 4 ft from the workbench
4 ft from the feed tray
wattage of safelight
7.5 watts - 3 ft distance
15 watts - 4 ft distance
can potentially affect radiographic imaging in a few ways, primarily by influencing the materials and equipment used in the process
humidity
are undesirable elements or characteristics that can appear on a radiograph and may interfere with the interpretation of the image
artifacts
_______ in the darkroom is designed to eliminate heat and fumes
ventilation
it refers to the image that exists on film after it has been exposed but before it has been processed
latent/potential image
black metallic silver image
visible/manifest image
RedOx
reduction and oxidation
EUROPE
electrons are used in reduction, oxidation produces electrons
activity of each individual components of reducing agent in solution is less than the activity when two components are combined
synergism/superadditivity
it is the any irregularity on an image that is not caused by the proper shadowing of tissue by the primary x-ray beam
artifacts
three major classifications of artifacts:
processing
exposure
handling and storage
it is an artifacts that occurs during processing any number of artifacts can be produced
P.I. Lines
Wet Pressure Sensitization
Gelatin Build Up
Emulsion Pickoff
Curtain Effect
Chemical Fog
processing artifacts
it is an artifacts that are generally associated with the manner in which the radiologic technologist conducts examination
Motion
Improper Patient Position
Wrong Screen Film Match
Poor Screen Contact Double Exposure
Warped Cassette
Improper Grid Position
exposure artifacts
it is an artifacts occurs during handling and storage
improper handling and storage
it is probably the most obvious artifact that caused by the build up of electrons in the emulsion
static marks
they are drying marks, characterized by whitish on the film caused by inadequate film drainage and an increased temperature or drying
bleb
are greenish white smudge at the film surface brought about the film touching each other in the area of the smudge during processing
kiss marks
are either black or white on the radiograph
streaks
these artifacts are half-moon shape densities which are the result of being subjected to pressure
crescent marks
it is the single most important content of the radiographic system, it is the part that produces x-rays
x-ray tube
parts of an x-ray tube
supportive housing
protective housing
glass/metal envelope
anode
cathode
3 types of supportive structure
ceiling support system
floor ceiling support system
c-arm support system
most frequently used support system
it consists of two perpendicular sets of rails mounted to the ceiling directly over the radiographic table
ceiling support system
interventional radiology suites often are equipped with this type of support system
it is very convenient because of its C-shaped, it can provide a very flexible x-ray tube positioning during in any interventional radiology procedure
most common variation used
C-Arm Support System
It maintains a vacuum inside the tube which allows for more efficient x-ray production and longer tube life
glass or metal envelope
the negative side of the x-ray tube that consists of filament and focusing cup
cathode
a coil of wire which is the source of electrons within the tube
2mm in diameter
1 or 2 cm long
filament
a metal cup where the filament is embedded
it serves to focus the space charge to a target area on the anode at the time of the exposure
focusing cup
the positive side of the x-ray tube
anode
it attaches the rotating target area to the rotor
it is made up of copper because of tis excellent conducting ability and this facilities the conduction of heat away from the target area
stem
it is a circular, disk-like structure with a slanted or beveled edge
it is made up of tungsten
target
it is the part outside the enclosure and consist of a series of electromagnets equally spaced around the neck of the tube
stator
it is a mechanism that is located inside the glass enclosure and a shaft made of bars of copper and soft iron fabricated in one mass
rotor
the __________ ________ or the control panel allows the radiologic technologist to monitor the x-ray tube current and voltage so as to make use of a useful x-ray beam that is appropriate in quantity and quality
operating console
the main purpose of the _______ switch is to connect the electrical power to the radiographic generator control device
on or off switch
the ________ _____ is located on the control panel console and serves as a means to determine the length of time x-rays will be produced
exposure timer
the _______ selector regulates the amount of electrical current that is being generated from a cathode filament
milliampere selector
______ is generated as the current flows through the filament of the cathode, causing thermionic emission
heat
this meter will provide information to the radiographer when it displays the total amount of electrical current flowing in and out of x-ray tubes from cathode and anode at exposure time
mA/mAs meter
this selector permits increases or decreases in the voltage across the x-ray tube at the time of the exposure
kilovoltage selector
this control switch causes the anode to rotate, turning to its maximum speed before the exposure is made
rotor
x-rays were discovered by Wilhelm Conrad Roentgen in _______ _, _____ by accident
November 8, 1895
anode heat: ______ shell
anode heat: outer shell
characteristics x-rays: _____ shell
characteristics x-rays: inner shell
bremsstrahlung: ______
bremsstrahlung: nucleus
interaction where projectile electrons interact with the outer shell electrons of the target atom
constant excitation
more than 99% of KE of projectile electrons is converted to heat
anode heat
interaction where projectile electrons interact with an inner shell electron of the target atom
primary beam 15%
characteristic x-rays
interaction where the interaction in which the electron can lose its KE
slowing down or breaking down
bremsstrahlung x-rays
it exits the body and travels in different directions with many energy levels
danger to the patient and radiographer, detriment to image quality
scatter radiation
the law states that radiation intensity is inversely proportional to the squared of the distance from the source of radiation
inverse square law
change in size and shape of the object as seen on the radiograph
distortion
it is the misrepresentation of the size and/or shape of the anatomic part of interest
distortion
any geometric misrepresentation of an anatomical structure on an image receptor that alters its true size and/or shape
distortion
two types of distortion
size distortion
shape distortion
is the enlargement of the recorded image from the actual size of the object
size distortion: magnification
unequal magnification of different portions of the same object
shape distortion
if the object plane and the IR plane are not parallel, distortion occurs
object position
thick objects are more distorted than thin objects
object thickness
only irregular anatomy shows distinct distortion
object shape
when the image appears to be shorted than the actual shape of the object
foreshortening
when the image appears to be longer than the actual shape of the object
elongation
a metallic barrier made of lead shutters with an aperture in the middle to limit the size of the beam
also called restriction
collimation
types of collimators:
diaphragm collimator
round/cylindrical collimator
rectangular collimator
to identify center of the x-ray field
a thin plastic sheet having a patient cross line is mounted at the end of collimator
fieldenter indicator
metal sheets placed in the x-ray beam between the window and the patient that are used to attenuate low energy (soft) x-ray photons
filtration
two types of filter
inherent
added
it is a type of filter where it is from components in the x-ray tube; glass envelope, insulating oil, diagonal mirror
thickness: 0.5-1mm Al
inherent filter
“added to”, additional materials are added in the path of beam for further filtration
it is a filter usually aluminum sheets
thickness: 1 - 1.5 mm Al
added filter
inherent filtration + added filtration
total filter
external filters placed on the collimator of the x-ray tube
trough filters
step wedge
boomerang
compensating filter
compensating filter used for chest radiography
trough filters
compensating filter used for long section of anatomy, translumbar, femoral arteriography, venography as well as foot
step wedge
compensating filter traditionally used during shoulder examination and facial examination
boomerang
