Test 1 Flashcards
negative end
cathode
positive end
anode
what is an x-ray?
- electromagnetic energy
- heterogenous invisible beam that passes through body tissue
different _______ determines how to interact with matter.
energies
differential absorption
Difference in absorption by different body tissues
radiographic density
blackness
radiographic density appears _______ on radiograph?
black metallic silver
radiographic density and anatomic density relationship
inversely related
radiographic contrast
degrees of contrast btwn black and white
why do we have contrast in image? How does it happen?
Allows to see something.
When the xray encounter dense material like bones.
What would the film look like if all of the x-rays interacted with the emulsion and the film was then processed?
it would be black
Is it really the x-ray that interacts with the film emulsion to produce the image?
no
What color of light do rare earth crystals typically emit?
greenish- yellow
x-rays have ______ wavelength = _____ energy
short wavelength
high energy
another name for single x-ray beam
photon
what determines energy of x-ray?
Amount of energy of each electron. (Short wavelength high energy)
mass of x-ray
no mass
charge of x-ray
no charge
electromagnetic energies in order of energy (relative to x-ray)
x-ray Gamma UV Visible light infrared microwaves radio waves
remove an electron from its orbit around a nucleus
ionize
energies in electromagnetic spectrum that have ability to ionize
x-ray
gamma
What makes an x-ray photon higher energy than a microwave?
short wavelength
high frequency
wave equation
velocity (speed of light) = wavelength x frequency
gamma ray
high energy radiation that doesn’t have mass
difference btwn gamma and x-rays
origin
Is a gamma ray always higher energy than an x-ray
no, relatively the same energy
do chiro’s use gamma rays?
no
Will exposure to x-radiation leave matter radioactive
no
To avoid being exposed to x-rays, how long must you wait before entering the x-ray room, after the exposure is terminated?
you can enter immediately
Why is a free electron in human tissue a worry?
can cause cancer
HOW MUCH OF THE ELECTRIC AND KINETIC ENERGY OF THE PROJECTILE ELECTRONS IS CONVERTED TO HEAT
99%
HOW MUCH OF THE ELECTRIC AND KINETIC ENERGY OF THE PROJECTILE ELECTRONS IS CONVERTED TO X-RAY?
1%
Is heat production an excitation or ionization interaction?
excitation
2 ways x-rays are produced
characteristics
bremsstrahlung
method of x-ray production that produces x-rays when electrons shift energy levels/shells within the atom?
characteristic
Tungsten is used as a target material. It has electron shells from “K” near nucleus to ____
P
Which characteristic x-rays of tungsten are useful enough to be useful?
K
at least _____ kVp is required to produce useful energy K-characteristic x-rays of tungsten
69.53 (70)
the characteristic x-ray with the most KeV of energy occurs from ___ to ___
P to K
Vast majority of x-rays in beam are result of _______ method
bremsstrahlung
in bremsstrahlung x-ray production, x-ray energies range from _____ to _____ KeV
0- 125 (machine stops at 125)
photographic properties of radiographic quality
density
contrast
geometric properties of radiographic quality
visibility
recorded detail (sharpness)
size
shape
mA and time of exposure controls
density
kVp controls:
contrast
relationship btwn mA and radiographic density
proportional
equation for mAs
mA * seconds
mAs determines # of
x-rays
as the kVp increases, the ____ of x-ray is increased
energy
degrees of difference btwn black, white and various shades of gray is property of:
contrast
transport of energy through space as a combination of electric and magnetic fields
electromagnetic energy
how is electromagnetic radiation produced?
electrons accelerating and decelerating
rays that have mass, massive compared to electrons
- more likely to ionize, take up space
- move fast
alpha rays
rays that have tiny mass, negative charge, slower than the speed of light
beta rays
_____ tends to cause SINGLE strand DNA to break
x-rays
______ tend to cause DOUBLE stranded DNA to break
alpha rays and beta rays
current that produces x-ray
DC
power companies use which current
AC
purpose of rectifier
convert AC to DC
do all electrons have same velocity as they pass from cathode to anode?
No
rectifier that produces a beam with the highest energy x-rays
high frequency rectifier
rectifier that reduces patient exposure by at least 30%
high frequency rectifier
rectifier that is the most consistent with the concept of ALARA
high frequency rectifier
rectifier that will extend the tube life
high frequency rectifier
rectifier that can be plugged in to a 110 outlet
high frequency rectifier
rectifier that produces the highest contrast radiograph
full wave rectifier
cost of full wave rectifier vs. high frequency
$3,000 to $5,000 more will cost the High Frequency
boiling off of electrons
thermionic emission
location where x-rays are produced in x-ray tube
focal spot
mAs is _____ related to radiographic density
directly
electrical unit to set console to accelerate electrons from cathode to anode
kVp
as kVp is increased, _____ of x-ray is increased
energy
degree difference btwn black, white and various shades of grey
contrast
anode spins to:
dissipate heat
rpm of the anode
3600
anode should spin ____ after the exposure is terminated to ensure no rotor bearing
at least 90 seconds
type of motor that spins anode
electromagnetic induction
current that spins anode
DC
target area of anode is made of
tungsten
anode target has ___ melting point
high
anode target has ____ atomic #
high
focusing cup has strong ____ charge to keep electrons focused into a small focal spot area on the target of anode
negative
360 degree divergence of x-rays from focal spot
isotropic
x-ray tube is filled with
nothing, its a vacuum
tube housing lined with
lead
tube housing filled with
oil
opening that allows x-rays out of tube housing
collimator
to produce x-rays, electrons flow from ____ to ____
filament (cathode) to rotating anode
thermionic emission takes place:
filament
___ and ___ make up electromagnetic induction motor to spin anode
rotor
stator
___ is spot where x-rays are produced
target
goal of anode heel effect
consistent/uniform radiographic density throughout film
anode side of tube can be located by:
positive label
listening for spin
finding wire for AC current
side of radiograph that will exhibit LEAST radiographic density
anode
high atomic # of tungsten ABSORBS _____ energy x-rays
low
anode side for lateral thoracic spine radiograph
down
anode side for lateral lumbar spine radiograph
up
anode side for AP thoracic spine radiograph
up
anode for full spine 14” x 36” film
up
anode side for lateral cervical spine radiograph
doesn’t matter on a 10X 12” film at 40
anode heel effect becomes important in terms of film size and SID
large film size at short SID
placing anode/cathode side in proper place affects the radiograph’s overall density by:
producing uniform density
how should tube be installed?
anode up
side of radiograph that is sharpest
anode
___ side of x-ray emits x-rays that are relatively perpendicular to the film
anode
since anode is always at top in chiro office, how do we get it to bottom
compensatory filters
anode for AP femur
down
72” film has to have _____ SID for anode heel effect
14X36
40” film has to have ______ SID for anode heel effect
14X17
