XR equip operation - Image Production 4.2 Flashcards
The law stating that the outer shell of an atom can contain no more than 8e is called
octet rule
Examples of particulate radiation are
helium nuclei, beta and alpha particles, protons, neutron
These have mass and energy.
The law states no more than 8e in outer shell but it does not stipulate that there must be 8e in outer shell
Particulate radiations are highly ionizing
Electromagnetic radiation travel
in waves of straight paths.
Bc it has mass, particulate radiation may travel along different paths
= XRs travel at what speed
at the speed of light - 186,000 miles per second
Wavelength is defined as the fr
peak to peak of the wave; crest to crest; trough to trough
Frequency is defined as
Number of waves passing a point per unit of time.
Higher frequency waves have shorter waves.
Lower frequency waves have longer waves.
Wavelenght and frequency
Inversely proportional to each other
The speed of xrays is based on
the fact that they are a form of electromagnetic radiation.
The speed of XR travel is constant, regardless of the factors used to produce them.
The XR beam changes as it travels through the pt by a process called
attenuation
Attenuation means XRs absorbed or scattered.
The INTENSITY OF RADIATION IS INVERSELY PROPORTIONAL TO THE SQUARE OF THE DISTANCE between the source of radiation and the person recving it. This describes the
the inverse square law
The answer will always result in 1/4 or 4times.
As radiation strikes matter
the energy is transferred to the atoms according to the law of conservation of energy.
Law of conservation states: energy cannot be created or destroyed; only changed in form. The energy is merely transferred.
Statements regarding ELECTROSTATIC CHARGES
- ES is the study of electric charges at rest.
2. ES charges concentrate on a conductor in the area of greatest curvature.
CURRENT/MAGNETIC FIELDS/CONDUCTORS
- A magnetic field always surrounds an electrical charge in motion.
- Current flows back and forth in AC
- Current flows in one direction in DC
- A conductor allows the flow of electrons
- The volt is the unit of potential difference
- The path of the electrical current is called the circuit.
ELECTROGMAGNETIC INDUCTION is the process of causing an electrical current to flow in a conductor
when it is placed in the magnetic field of another conductor.
Electromagnetic induction does not req to touch each other.
2 types of electromagnetic induction are
self-induction and mutual-induction
The strenght of the magnetic fields in a transformer is increased by
coiling the wires and letting their magnetic fields overlap.
This intensifies magnetic field making tansformer more efficient.
Electricity is supplied to XR room by way of
generator
mechanical to electrical energy
The electricity provided to the radiology dept is
60Hz AC
This equals 60 cycles per second;
At 110 or 220 volts
The electricity provided to the radiology dept operates on
120 pulses per second
This equals 60 cycles per second
bc it cycles back and forth 120 times per second.
High-frequency power
has almost NO ripple.
Low ripple = high average photon energy
The primary advantage of 3 phase power is
voltage never drops to zero.
3phase power produces higher average photon energy than single phase power
A variable transformer that is used to SELECT KVP for the XR circuit is the
Autotransformer
What is the transformer used to BOOST VOLTAGE to kilovolts level called
Step-up transformer
The voltage is varied at the autotransformer.
Then boosted to KV level at the step-up transformer
A transformer that has more turns in the secondary coil than in the primary coil is called
Step-up transformer
Transformer is named for what it does to voltage.
Voltage coming to the XR machine is kept constant through the use of a
Line Voltage Compensator.
The older XR machine req to manually set; whereas the newer XR’s let machine do adjustment.
Step-down transformer
steps down voltage
Where does thermonic emission occur
cathode
Thermonic emission is boiling off e fr filament wire
Which device is pre-reading
kvp meter
indicates what kvp will be after it steps-up
Hence: pre-reading
What device reduces voltage and provides current to produce an e cloud/ or space charge at the filament
Step-down
And is located in the filament circuit
What device is electronic, with settings as low as .001 sec
timer
Timers are accurate as low as 1/1000s, 1ms, .001s.
Which of the following is surrounded by a negatively charged focusing cup
Filament
Focusing cup/ filament are part of cathode assembly.
Focusing cup has negative charge at time of exposure in order to repel e fr cathode.
Bc same charges repel.
