exam 1 questions Flashcards
all of these affect contrast
kVp
(contrast is mA)
what is the inherent filtration, list 2 examples
insulating oil
metal housing
glass envelope
Explain qualitative digital analysis? 2 examples
- using algorithms to mathematically change density values to predetermined numerical values
- magnification and edge enhancement
picture of CCD digital sensor taken apart
- which one reads the electrical signal
- which one converts visible light to electrical signal
- dark purple with chips
- light purple
what increases magnification
increased object to receptor distance
or
decreased source to object
what wave has the most energy
the one with with the highest frequency
transmission of energy through space and matter
radiation
explains propagation of radiation (creating)
wave theory
explains interaction of radiation with matter
quantum theory (interacting/mass)
shorter wavelength=
_____frequency
_____energy radiation
shorter wavelength
higher frequency
higher energy radiation
non-ionizing examples
radiowaves
microwaves
infrared radiation
visible light
~ultraviolet light
ionizing
(have sufficient energy to eject electron from the shells)
x-rays
gamma rays
WEIGHTLESS packages of pure energy (photons) without an electrical charge which travel in waves with specific freq and wavelength at speed of light and ionize matter
xrays
list properties of xrays
- travel in straight line
- invisible, weightless, no charge
- travel at speed of light
- high penetrating(short wavelengths)
- can ionize matter
- differentially absorbed by matter
- produce biological changes
minimm energy required to remove proton from nucleus
binding energy
energy needed to remove an electron from its shell
binding energy
what is the focusing cup made of and what is its charge
molybdenum
negative
picture of xray tube and asks what dissipates heat
copper stem
picture of xray tube and asks what creates the electrons
tungsten filaments
(emits electrons)
the transformer that brings 110 volts to 3-5 volts and is controlled by what
step down transformer
controlled by mA
what increases sharpness
increase source to object distance
why did it take so long to switch from film to digital
expensive equipment and patient comfort
or expensive and image quality
In the production of a digital image in CMOS, what does the x-radiation get converted to?
visible light-> what the scintillator does
how fast does the xray travel in vacuum
speed of light
what is true about copper and tungsten
K shell of tungsten is more energy than L shell
characterisitic radiation
electron to electron
bremsstrahlung radiation
electron to nucleus
which one has lowest radiation
film
CMOS
CCD
CCD
what is CCD
direct
why is low vapor pressure important
maintain vacuum
BW where contacts are overlapped, what is wrong
horizontal angulation is off
Picture of X-ray head and says what must be maintained in space 5?
vacuum
What is the point of line-principle system?
used to dissipate heat and increase resolution
what does rectifier do to electrons
always go cathode to anode
what does rectifier do
turn alternative to direct and go cathode to anode
if it hits nucleus directly, what energy is released and what type of xray
maximum energy released
bremsstrahlung
matter is
mass and takes up space
Edge enhancement does what?
simulate or hide disease states
if you increase____ then the ___ of electrons will increase
mA
amount of electrons
which element is associated with film
silver
what is non ionizing radiation
microwaves
radiowaves
microwaves
infrared rays
visible light
ultra violet light
what has the best spatial resolution
film
definition of thermionic emmision
when filament is heated with low voltage source and emits electrons at a rate proportional to its temperature
When object and receptor are not parallel and beam and receptor are perpendicular?
teeth appear shorter
smaller focal spot
higher spatial resolution
Decrease sharpening:
larger focal spot
def of quality
mean energy of the xrays
high contrast needs ____kVp
low
parts of cathode
tungsten filament
and focusing cup (molybdenum)
if you want to keep density the same and double mA, what would u do to time
half it
Electron from inner gets knocked out and electron from outer fills in
characteristic
Which of the following requires the use of chemical interactions to produce a radiographic image?
a. CMOS
b. PSP
c. Film
d. CCD
film
rate of loss of energy from a particle as it moves through matter
ionizing rate
process of forming positive and negative ion by removal of electron from neutral atom
ionization
