Chapter 15 Flashcards
the source of the x-ray beam in an x-ray tube
anode target
device used to decrease scatter radiation
grip
general amount of blackness in a radiographic image
density
electromagnetic radiation of shorter wavelength than light
x rays
source of x rays in a dental or portable x ray machine
stationary anode
the distance between the source of x ray and image receptor
focal film distance
range of shades of grey allowing both bone and soft tissues to be seen at the same exposure setting
dynamic range
weakening of sound waves as they enter the body
attenuation
device used to make grid lines invisible
potter bucky diaphragm
decrease in the strength of the x ray beam near the anode
heel effect
current applied to the cathode filament
milliamperage
ability to distinguish two adjacent structures on an image
spatial resolution
energy that breaks chemical bonds and damages dna
ionizing radiation
serves as stationary source of x ray beams
rotating anode
difference between blacks and whites in an image
contrast
source of electrons in x ray tube
cathode
sharpness of radiograph
detail
dark structure on radiograph
anechoic
b mode
brightness mode
radiograph made with cassette
computed radiography
radiograph uploaded digitally to a computer
digital radiograph
diagnostic imaging technique used to image moving structure
fluoroscopy
structure that produces more echoes than surrounding structures
hyperechoic
measurement of sound frequency
Hz
structure that has the same brightness as adjacent structures in an ultrasound
isoechoic
m-mode
motion mode
computer system used to permanently store and transmit digital images to different computers within a single location or between locations
PACS
measurement of absorbed radiation that takes into account biological effectiveness of radiation
gray
unit of absorbed dose of ionizing radiation
sievent
changing kVp from 50 to 60, changing the focal film distance, removing grid
increases radiologic density
changing mA from 300 to 200, changing exposure from 1/2 s to 1/4 s
decreased radiologic density
changing objective film distance from 6 to 12 inches, changing from detail screens to fast screens
does not change density
reflection of beam when encounters air or gas
reverberation artifact
layered appearance when US beam cuts through edge of cystic structure and solid tissue
shadowing
area of darkness resulting from inadequate sound beam penetration through highly reflective or absorbing tissue
acoustic enhancement
refraction or redirection of the sound beam helpful in identifying round structures
edge artifact
duplication of an image as a result of reverberation
mirror-image artifact
when ultrasound beam passes through structure with low attenuation
slice-thick artifact
part where x ray exits tube
window
part produces electron cloud when current in applied
filament
high voltage circuit controls electrical potential between cathode and this part
anode
part that encases other parts of the tube
glass envelope
x rays do not emanate from this negatively charged pole
cathode
part that directs electrons towards anode
focusing cup
electrons directly impact this part to produce x ray
anode target
the shorter the wavelength of rays…
the greater the energy and penetration
kV controls what
electrical potential between cathode and anode
where electrons impact anode
“target”
photostimulable phosphor plate is used for what
compound radiography
