Review PPT Flashcards
What part of the x-ray tube has the following:
Made of lead glass
Window of non-lead glass
Evacuated glass envelope
the electrons of particulate radiation is made up of what
beta particles
cathode rays
We know that 99% of kinetic energy goes to heat dissipation, what are the 3 steps the dissipation occurs through?
heated tungsten block –> copper block –> insulating oil
What kind of action of ionizing radiation is this?
Radiation interacts with the biologic molecules of the body
Direct
What % is Compton scattering regarding interactions of x rays with matter
~57%
Regarding equivalent dose:
X radiation –> 1 Gy =
1 Sv
high-energy radiation, capable of producing ions
Ionizing radiation
What patient protection?
Protection of the thyroid gland and gonads
Very radiosensitive areas
Aprons and thyroid protectors
transmission of energy through space and matter in the form of
waves or particles
radiation
What is this:
electrons (negative charge)
Orbitals
What is the formula for effective dose
Equivalent dose x Wt
What are the 3 GUIDING PRINCIPLES IN RELATION TO RADIATION PROTECTION
Justification
Optimization
Dose Limitation
particulate radiation is made up of what 4 things
alpha particles
protons
electrons
neutrons
what dentition?
before 1st molar erupts
primary
Unstable ions, atoms or molecules with an unpaired
electron, which tends to rapidly associate with other molecules
Free radicals
creation of an ion
ionization
What is the current in the tungsten filament
3-10V
What % is coherent scattering regarding interactions of x rays with matter
~7%
Maximum scattered radiation will be backwards - example:
____ to _____ degrees from the primary beam as it ENTERS the patient
90 to 180
What part of the x-ray tube has the following:
Tungsten (focal spot)
Copper block (thermal conductor)
Anode (+)
Which guideline principle?
The radiation dose to the patient should be kept as low as possible
A.L.A.R.A - As Low As Reasonably Achievable
Optimization
Regarding imaging receptors - the most ______ receptor compatible with indicated
examination should be used
sensitive
What % is photoelectric absorption regarding interactions of x rays with matter
~27%
Who did research with cathode rays and special screens that glowed when exposed
Wilhelm Röntgen
What personnel protection?
The team must leave the room or use barrier protection, when
needed, which should contain a glass window with lead
Protective barriers
Regarding equivalent dose:
alpha radiation –> 1 Gy =
20 Sv
What is this:
protons (positive charge) and neutrons
atomic nucleus
In particular, the operator is not to stand on the side of the patient _______ the x-ray tube as this would expose them to the ______ x-ray beam EXITING the patient
opposite ; direct
These are examples of what kind of ionizing radiation:
imaging exams
radiography & tomography
diagnostic
What kind of action of ionizing radiation is this?
Radiation interacts with the water molecules present in the body and then with biologic molecules
indirect
spontaneous nuclear disintegration process of a molecule to acquire a more stable form
radioactivity
What unit for measuring quantities of radiation is this?
The total energy absorbed by any type of ionizing radiation per unit of mass of any type of matter
Gray (Gy)
Absorbed dose
Which guideline principle?
Benefit of the diagnostic exposure exceed the Risk of harm
Justification
the alpha particle of particulate radiation is made up of what
2 protons
2 neutrons
Who experimented with vacuum tubes and noticed a greenish fluorescence on plates that were away from the tube
Wilhelm Röntgen
what radiation has enough energy to overcome the electron binding energy
Ionizing radiation
Who noticed distance > cathode rays
Wilhelm Röntgen
What are the following?
Change or loss of a base
Breakage of a single DNA strand
Breakage of both DNA strands
Cross-linking of DNA strands to other DNA strands or to proteins
DNA Changes - Damages
What theory of electromagnetic radiation is this:
Small discrete bundles of energy (PHOTONS)
Contains a specific amount of energy (electron volt - eV)
quantum theory
These are examples of what kind of ionizing radiation:
radiotherapy
cancer treatment
Therapeutic
Generally, the position of minimum exposure will be at ___ degrees from the primary beam as it EXITS the patient
45
When it is not possible to use barriers or leave the room, never:
Hold the receptor in _____
position
Maximum scattered radiation will be ______
backwards
Which guideline principle?
The individual effective dose shall not exceed the limits recommended by the ICRP
Occupational and general public
Dose limitation
Spectrum of photons emitted from an x-ray machine operating at 70 kVp –>
The vast preponderance of radiation is _________ radiation
with a minor addition of ________ radiation
bremsstrahlung ; characteristic
an atom is composed by what 2 things
atomic nucleus
orbitals
filter out the photons with less energy
filtration
the exposure button has active ______ voltage
high
What x-rays?
Dental stage of development = adolescent (no primary teeth & before 3rd molars erupt)
Type of Exam = Growth & Development OR Dental/Skeletal Relationships
As needed
PANO/PAs to access 3rd molars
What theory of electromagnetic radiation is this:
Travel at the speed of light in a vacuum
Are described in terms of their wavelength and frequency
wave theory
What unit for measuring quantities of radiation is this?
Biological effects of different
types of radiation, weighted for
each type of tissue
Sievert (Sv)
Effective dose
What % is no interaction regarding interactions of x rays with matter
9%
Regarding source-to-skin distance:
The _____ the distance, the less _____ the photons will be,
and the lower the irradiated area
longer ; divergent
What unit for measuring quantities of radiation is this?
Biologic effects of different types of radiation
Sievert (Sv)
Equivalent dose
When it is not possible to use barriers or leave the room, never:
Neither the operator nor the patient should hold the ________
x-ray tube head
When it is not possible to use barriers or leave the room, never:
Stand in the direction of the _____ beam
primary
limits the amount of radiation
collimation
What part of the x-ray tube has the following:
Tungsten filament (source of electrons)
Concave molybdenium bowl (focusing cup)
Cathode (-)
smallest particle of an element having the characteristics of the element
atom
Maximum dose will generally be in line with the primary beam as it ______ the patient
exits
The high voltage circuit has a current of _______ and _______ rays
electrons ; cathode
Upon reaching tungsten target:
kinetic energy –> x-rays = ____%
kinetic energy –> heat = _____%
x-rays = 1%
heat = 99%
What patient protection?
They should be used whenever possible
Reduce the number of repetitions
Receptor holding devices
There is ____ defined dose limit for patients
NO
Who revolutionized the diagnostic resources in the medical and dental fields in 1895
Wilhelm Röntgen
