1. Chapter’s 2, 3. & 4 By Garland Fisher
Radiology
Chapter’s 2, 3. & 4
By Garland Fisher

2. Electromagnetic spectrum
Unique abilities
Some rays visible some are not
Penetrates matter
Produces latent image
Produces fluorescence
Light bulb
Produces ionization of matter
Change matter

3. Matter Anything that occupies space and has mass
Matter can be altered by energy
Fundamental unit of matter is the Atom
Desk
Chair
Computer
Tissue
Muscle
Teeth
Bone
Your Patient

4. Atom
Electrons
An atom is the smallest unit of an element, it consist of a positively charged protons found in the nucleus. Negatively charge electrons that orbit around the nucleus.
Neutron
Proton
Electron

5. Nucleus (Dense core that occupies very little space)
Protons
Subatomic particles and positively charged
Neutrons
Subatomic particles and has no charge

6. Nuclear Composition Is this Atom stable or unstable?
Equal number of protons and electrons form a stable atom.
The number of protons and neutrons equals the atomic weight.
Force will knock an electron out of their orbit.
X-radiation
Electromagnetic energy
Is this Atom stable or unstable?

7. Ionization (production of ions)
Converting atoms into ions.
To produce ions a force or a collision such as x-radiation or electromagnetic energy must eject an electron out from its orbit. Thus making the atom unstable.
Spontaneous release excess energy in the form of wave or particles.
ION

8. Electrostatic Force Binding energy holds electrons in their orbits (Example: sun and the planets)
There are seven shells an atom can have they are k, l, m, n, o, p, and q.
K-shell has the highest energy and the strongest binding energy
Nucleus k l m n o p q

9. Atoms into ions Positive ions are ionized atoms.
An ionized atom has been interrupted by some force:
X-radiation
Electromagnetic energy
Negative ions are electrons out of orbit or unstable structures.
This ejected ion will speed off to interact with other atoms.
When they interact or collide it sets off a chain reaction and in turn will eject other electrons until the energy dissipates.

10. Elements
Elements
Substances made up of only one type of Atom

11. Molecule Molecule Two or more Atoms make up a molecule
Two Hydrogen and one Oxygen = Water
Bonded together by electrons on the outer most shells

12. Ionizing Radiation (all radiation cause biological changes)
Particulate
Responsible for radioactivity
Radioactivity is when atoms spontaneously disintegrate or decay.
Power plant
Atomic bomb
Electromagnetic
Series of wave like energies with no mass some high energy some low energy
Visible and invisible
Man made or natural occurring

13. Electromagnetic Energy
Made up of both wave and particle that travel in a straight line
X-ray = bundle of energy, is termed, x-ray photon which has no mass no charge and travels at the speed of light (186,000 MPS)
X-ray photon is what interacts with matter (your patient)

14. Examples of electromagnetic radiation and there wave like patterns
Less energy
More energy

15. Electromagnetic Energy
Wavelength
Distance between the crest of the wave to the next wave
Frequency
Refers to the number of wavelength that pass a given point in a certain amount of time. We can adjust the frequency by kilovoltage

16. Voltage
Measurement of electrical force that cause electrons to move from a negative pole to a positive one (Strength)
Dental x-ray units require a high level of electrical potential

17. Kilo-Voltage Peak (KVp)
Kilovoltage controls the level of penetration
Shorter wavelength = more penetrating
High frequency =
more penetrating
Longer wavelength = less penetrating
Low frequency the = penetrating
Kilovoltage
Kilo = 1000
Volatage = volts 110 or 220
Higher voltage means greater energies
Dental radiographs require 65 to 100 kilovolts
Higher KVp should be used when area is dense or thick
Adjust KVp on individual diagnostic needs
Overall QUALITY of primary beam

18. Amperage Measurement of electrons moving through a conductor
Current is measured in amperes

19. Milliamperes (mA) Milliampere Milli = 1/1000
Ampere = Electrical current NOT voltage
mA settings
7, 10, and 15
Thermionic emissions
Higher the setting increases temperature resulting in some electrons being ejected out of their orbit.
Ampere allows electrical current to flow thru a filament which results in a cloud of electrons
Depending on mA setting will depend on the QUANTITY of x-rays produced

20. Milliamperes-Seconds
Exposure time
Interval of time in which photons are being produced (.117 secs)
Longer time = more photons
High mA = more photons
Both mA and exposure time both have a direct influence on the number of electrons produced
If we produce to many photons our dental film will be dark or black

21. Radiographic Density (Degree of darkness or blackness of an x-ray.)
Amount of radiation reaching the film
KV or mA
Distance from the x-ray tube to the patient
Patient thickness (Density)
Developing conditions
The more photons that strike the film the more dense (black) the radiograph will appear

22. Tubehead
Cathode
Negative electrode consist of tungsten filament held in a cup shaped holder made of molybdenum
Negative = electrons, therefore electrons are created to produce photons *
Electrons held in place

23. Tubehead
Anode
Positive electrode consist of a wafer thin tungsten plate embedded in a solid copper rod
Positive = collision = photons *
Collision produced photons (indicated in red)

24. Transformers Three types are used in production of x-rays
Step down
decreases the voltage from the incoming 110 or 220 to three to five volts required
Step up
Increases the voltage to 65,000 to 100,000 volts required
Autotransformer
Compensator

25. Inside the Tubehead

26. This is What Happens
Electricity excites the filament at 3-5 volts, creating thermionic emissions, a release of electrons from the tungsten filament when heated, this cloud of electrons stay in place until the exposure button is pushed. The high voltage circuit is activated. The electrons produce are accelerated across the x-ray tube to the anode. The molybdenum cup helps to direct the electrons to the tungsten target. When the electrons strike the tungsten target their energy of motion or kinetic energy is converted to x-ray energy and heat. More heat is created that x-rays and is dissipated through the copper stem and absorbed by the insulating oil. X-rays are produce in all direction only a few will escape through the unleaded portion of the tube. Those x-rays will be directed to the aluminum filter, which will remove the long waves. The collimator will focus the remaining short waves and travel down the lead lined PID and exit the tubehead

27. Production of radiation (not all produce the same in the tube head)
General radiation
AKA braking radiation
An electron passes near the nucleus and is deflected by the positively charge nucleus
Once deflected this kinetic energy is converted into photons
Add photo
Bremsstrahlung German
(braking radiation)

28. Production of radiation (not all produce the same in the tube head)
Characteristic radiation
Electron that has been deflected continues to travel ejecting other electrons out of orbit until they loose their kinetic energy
Energy in motion