Physics Flashcards
does mAs have an affect on receptor exposure
yes, direct
does kVp have an affect on receptor exposure
yes, direct
does FSS have an affect on receptor exposure
no
does SID have an affect on receptor expsoure
yes, indirect
does OID have an affect on receptor exposure
yes, indirect (increase OID, decreases receptor exposure)
does CR angle have an affect on receptor expsoure
yes, indirect (increase angle, decreases receptor exposure)
does grid use have an affect on receptor exposure
yes, indirect (add grid, decrease receptor exposure)
does collimation have an affect on receptor expsoure
yes, indirect
does tube filtration have an affect on receptor exposure
yes, indirect
does patient thickness have an affect on receptor exposure
yes, indirect
does patient motion have an affect on receptor exposure
no
does mAs have an affect on contrast
no
does kVp have an affect on contrast
yes, indirect
does FSS have an affect on contrast
no
does SID have an affect on contrast
no
does OID have an affect on contrast
yes, direct (increase OID, increase contrast)
does CR angle have an affect on contrast
no
does grid use have an affect on contrast
yes, direct
does collimation have an affect on contrast
yes, direct
does tube filtration have an affect on contrast
yes, indirect
does patient thickness have an affect on contrast
yes, indirect
does mAs have an affect on spatial resolution
no
does kVp have an affect on spatial resolution
no
does FSS have an affect on spatial resolution
yes, indirect
does SID have an affect on spatial resolution
yes, direct
does OID have an affect on spatial resolution
yes, indirect (increase OID, decreases spatial resolution)
does CR angle have an affect on spatial resolution
yes, indirect (increase angle, decreases spatial resolution)
does grid use have an affect on spatial resolution
no
does collimation have an affect on spatial resolution
no
does tube filtration have an affect on spatial resolution
no
does patient thickness have an affect on spatial resolution
yes, indirect
does patient motion have an affect on spatial resolution
yes, indirect
what factors affect receptor expsoure
-mAs
- kVp
- SID
- OID
- CR angle
- grid use
- collimation
- tube filtration
- patient thickness
what factors affect contrast
- kVp
- OID
- grid use
- collimation
- tube filtration
- patient thickness
what factors affect spatial resolution
- FSS
- SID
- OID
- CR angle
- patient thickness
- patient motion
what is the grid ratio equation
height/width of interspace
equation for maintenance/direct law
mAs1/mAs2 = (d1/d2)^2
equation for inverse square law
I1/I2 = (d2/d1)^2d
the primary portion of the step up transformer is in what circuit
primary/low-voltage circuit
the secondary portion of the step up transformer is in what circuit
secondary/high-voltage circuit
the autotransformer is in what circuit
primary/low-voltage circuit
the step down transformer is in what circuit
filament circuit
the rheostat is located in what circuit
filament circuit
the x-ray tube is located in what circuit
secondary/high-voltage circuit
the filaments are located in what circuit
filament circuit
the milliampere meter is located in what circuit
secondary/high-voltage circuit
the rectifier bank is located in what circuit
secondary/high-voltage circuit
the timer circuit is located in what circuit
primary/low-voltage circuit
variable resistor
rheostat
who invented x-ray
Wilhelm Roentgen
when was x-ray invented
November 8, 1895
first casualty to radiation
clarence dally
speed of light
3x10^8 m/s ; 186,000 miles/sec
unit of absorbed dose
gray (Gy)
used to measure occupational dose; dose equivalent
sievert (Sv)
output of the radiographic unit’s radiation measurement in air
coulomb/kg
measures radioactive marerial
becqueral (Bq)
largest natural source of radiation
radon
what is the relationship between energy and frequency
direct
what is the relationship between energy and wavelength
inverse
what is the relationship between frequency and wavelength
inverse
loss of energy as it goes through matter
attenuation
blurring of the edges
punumbra
how much leakage is the housing allowed
1 mGy/hr at 1 meter
what are the filaments made of
thoriated tungsten
melting point of tungsten
3410 degrees C; 6152 degrees F
boiling off of electrons
thermionic emission
can’t boil off/produce anymore electrons
saturation current
what is the focusing cup made up of
nickel - negatively charged
what is the housing of the x-ray tube made of
lead
what is the target of the anode made of
tungsten with rhenium
atomic number of tungsten
74
what are the neck and base of the anode made of
molybdenum
how does the anode rotate by
induction motor
as you decrease the angle of the anode what happens to the anode heel affect
increases
correction factor of single phase generator
1.0
correction factor of three-phase 6 pulse generator
1.35
correction factor of three-phase 12 pulse generator
1.41
correction factor of high frequency generator
1.45
what letter represents atomic mass number
A
what letter represents atomic number
Z
what is the last shell called
valence shell
electron binding energy of the k shell of tungsten
69.5 keV
electron from filament stream knocks out the k-shell electron causing a cascade
characteristic radiation
filament electron gets attracted to the nucleus and breaks/slows and changes direction
brehms
the reason we filter is due to what
brehms
happens under 69.5 kVp
brehms
max electrons the last shell can have
8
formula to find number of electrons in a shell
2n^2
what is frequency measured in
hertz
what is wavelength measured in
meters
what is planks constant
4.135x10^-15 eV sec; 6.626x10^-34 J sec
height of wave
amplitude
how many pulses is 60 cycles
120
what does 1 hz equal
1 cycle per second
formula for velocity
v=f x wavelength
x-rays are considered what two things
non-threshold and linear
what is alpha particle made of
2 protons and 2 neutrons
what are beta particles
electron ejected from the nucleus
if the beta that is emitted has a positive charge is is called what
positron
what does 1 coulomb equal
6.25x10^18 electrons
ohms law
V=IR
what is resistance measure in
ohms
what is current measured in
amps
what is electric potential measured in
volts
what type of current is in the vacuum tube
direct current
how do you find resistance in a series circuit
add them all up
how do you find resistance in a parallel circuit
1/RT=1/R1+1/R2+1/R3 (lowest is almost half of total)
turns AC into DC
rectifier
device that changes voltage and current
transformer
conductor fashioned into a coil
solenoid
when you add an iron core into the solenoid it creates what
electromagnet
