Jeopardy Review Flashcards
What is the Law of Conservation? Give an example of it.
Matter and energy cannot be created or destroyed but they can be converted.
Example- kinetic to heat
What is the electromagnetic spectrum?
The range of wavelengths and frequencies of electromagnetic radiation from gamma to radio waves
What is absorbed dose is measured in? What is the standard unit of measurement for dose equivalent?
rad, gray (Gy) rem, sievert
What is binding energy? Which shell has the highest binding energy?
The amount of energy needed to remove the electron from the atom. “K”
Name 4 properties of x-rays out of 12
Travel in straight lines, at the speed of light, create heart, cannot be focused, cause effects, invisible penetrating
How are wavelength and frequency related?
Inversely
What effect is evident in the irradiated person? What is an example of genetic effect that may occur in a descendant of an exposed individual?
Somatic
&
Genetic
X-rays are classified as which type of energy?
Electromagnetic
What are the 3 cardinal rules of safety?
Time, distance, shielding
What is a small bundle of energy referred to as?
Photon
What is the most efficient generator and what is its ripple effect?
High frequency
<1%
Which transformer is associated with mA selector? Which transformer is associated turning volts into kilovolts?
Step-down & step-up
Define mutual induction
Two coils are placed next to each other. A current will run through the first causing a similar current in the second.
Which current do transformers operate with? What type of current is necessary to operate an X-ray tube?
Alternating current (AC) & direct current (DC)
The principle of self- induction is demonstrated in this device
Autotransformer
Name the 3 critical transformers in an
x-ray circuit
Autotransformer
Step-up
Step-down
What is the penetrating power of the x-ray beam? What controls the quantity or number of photons in the beam?
kV- quality
mA- quantity
When electrons move in one direction and then reverse and move in the opposite direction it is called?
Alternating
Current
What is the function of a generator?
Converts mechanical energy into electrical energy
How many direction(s) do electrons flow in a rectifier?
One
What type of anode is mainly used today in radiology? What is it made of?
Rotating
Tungsten and molybdenum
What is the main function of the rotor? Where is it located?
To rotate the anode. Located on the anode end inside the x-ray tube.
Describe thermionic emission
The boiling off or burning off of electrons at the filament (cathode end)
What affect does focal spot size have on an image?
The smaller the focal spot the better the image detail and vice versa.
What percentage of the kinetic energy is converted to heat when moving electrons strike the anode target?
99 %
What is the
negative portion of the tube called? The
positive?
Cathode
Anode
Name 4 different table features.
Difficult to scratch, free of crevices, tilt or fixed, radiolucent
What is the function of the timer circuit?
Regulates exposure termination
Modern AEC’s have a minimum reaction/response time in the region of __
second.
.001
What type of switch is the
exposure switch classified as?
Deadman switch
The backup time should be set at what percent of the anticipated manual exposure time?
150 %
Name the two types of X-ray units.
Diagnostic
Therapeutic
What happens to electrical signal when multiple ion chambers are used at once?
Signal is
“averaged” from .
each used chamber.
What is APR?
Anatomically programmed radiography- built in technique chart in the computer
How are the ion chambers
positioned on the upright and table bucky?
Mickey looking
Where is an
ionization chamber located? What is its main function?
(In front of the IR)
Preset to terminate when enough x-ray energy has been received.
What is the principal factor that AEC controls?
Time
What are two types of AEC systems?
What is another name for AEC?
Phototimers and ionization
chambers- (AED)
Only electrons which drop into what shell will produce characteristic photons within diagnostic x-ray range?
“K” Shell
Which spectrum has continuous emissions and a wide variety of energy levels?
Brem’s
What are the electrons from the thermionic cloud that arrive at the anode target referred to as?
Incident electrons
What is the velocity of accelerated electrons?
Range from ½ speed of light to nearly the speed of light
Target interactions occur within the top __ of the anode surface?
.25-.5 mm
Electron Interaction with Target Atoms produce X-RAYS by which 2 processes?
Bremsstrahlung
Characteristic
What is binding energy? Which shell has the highest binding energy?
The amount of energy needed to remove the electron from the atom.
“K”
Describe the line focus principle
The relationship between the effective focal spots and the actual focal spots of the x-ray tube.
What makes up the cathode assembly?
What makes up the anode assembly?
Filament
Focusing cup
Associated wiring
Anode
Rotor
Stator
What is the stator and where is it located?
Electromagnets (which induce movement in rotor) located outside the glass or metal envelope
Describe the anode heel effect
Radiation intensity is greater on the
cathode side of the x-ray beam due to the geometry of the anode.
What is the function of the exposure switch?
What does it activate?
Permits current to flow through the circuit; it activates the rotating
anode of the x-ray tube.
What is the main circuit?
Supplies x-ray tube with properly modified power to produce x-rays.
What is the
filament circuit?
Supplies filament with properly modified power to create an appropriate thermionically emitted electron cloud.
What is the purpose of the backup time circuit? What is the max exposure per U.S. law?
To protect the patient and the x-ray equipment;
600mAs
List 3
conditions/materials that would be a reason to increase density
Ascites
Pneumonia
Contrast media
What are 4 critical factors to be aware of when using AEC?
Collimation
Patient positioning
Chamber selection
Subject density
IR size
Describe what happens when incorrect ion chambers are selected for an exam.
Can result in over or underexposure to IR.
Also, can lead to possible exam repeats and more dose to patient
What is density adjustment and where is it found?
Permits adjustment of detector sensitivity; on console monitor
Describe a
characteristic interaction
Occurs when an incident electron interacts with an inner-shell electron, the incident electron will continue but in another direction.
Describe a
bremsstrahlung interaction
When an incident electron interacts with the force field of the nucleus, the force field causes the electron to slow down or brake and the electron loses its energy and emits a photon.
Name four factors that can change the amplitude of the emission spectrum graph.
mA kVp
time filtration target material generator efficiency
Between 80 and 100 kVp about 80-
90% of the primary beam is produced by? And the rest of the 10-20% is produced by?
Brem’s
Characteristic
