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53 Cards in this Set

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Is the smallest particle of an element that still retains the properties of the element

Background Radiation

Ionizing radiation that is always present in our environment.

Such as:

1. Cosmic radiation from outer space

2. Terrestrial radiation from the earth and its environments (Radon Gas)

3. Naturally occurring radionuclides that are deposited in our bodies by inhalation and ingeston.

Beta Particle

A form of particulate radiation/ High speed negative electrons

Coherent Scattering

Radiation that is scattered when a low- energy x-ray passes near an atoms' outer electron.

How much of the of the interactions of matter with the dental x-ray beam are the result of coherent scattering?


Compton Effect (scattering)

Only a part of the dental x-ray energy is transferred to the electron, and a new weaker x-ray is formed and scattered in some new direction opposite of the original x-ray.

Photoelectric effect

all or nothing energy loss

the x-ray imparts all its energy to an orbital electron of some atom

All of the energy from the photon is absorbed by the displaced electron in the form of Kinetic energy


Is unstable isotopes that are radioactive and attempt to regain stability through the release of energy

Electrons have what kind of charge and are constantly doing what around the nucleus?

Has a Negative Charge and constantly in motion orbiting the nucleus

Protons have what kind of charge and determines what?

Has a positive charge

The number of protons in a nucleus of an element determines its atomic number

Neutrons have what kind of charge

Have no Charge

What is Ionization

is the formation of ion pairs

What is an ion

are atoms that have lost or gained an electron

Defined as a charged particle

A positive ion

Has more protons than electrons

What is it called when atoms have gained or lost an electron and are electrically unstable?

an ION


When an atom is struck by an x-ray photon, an electron may be dislodged and an ion pair is created.

As high- energy electrons travel on, they push out electrons from the orbits of other atoms. Creating additional ion pairs

These unstable ions attempt to regain electrical stability by combining with opposite charged ions

All 3 statements are true


the emission and movement of energy through space in the form of electromagnetic radiation of particulate radiation.

is the process where by certain unstable elements undergo spontaneous disintegration in an effort to attain a stable nuclear state.

Do Dental x-rays use radioactivity?


Electromagnetic Radiation

is the movement of wavelike energy through space as a combination of electric and magnetic fields.

What properties does the electromagnetic spectrum have? (6)

1. travel at the speed of light

2. Have no electrical charge

3. Have no mass or weight

4. Have energies that are measurable and different

5. Pass through space as particles and in a wavelike motion

6. Give off an electric field to= right angles of their path of travel and

a magnetic field to= right angles to the electric field


Bundles of energy that travel through space at the speed of light

Wavelength definition ?

Whats it measured in?

does it have a direct or indirect relationship to radiation?

Is the distance between two similar points on two successive waves.

Measured in Angstrom

INDIRECT- The shorter the wavelength the more penetrating the radiation.

Frequency definition?

Whats it measured in?

Does it have a direct or indirect relationship to radiation?

Is a measure of the number of waves that pass a given point per unit of time.

Measured in Hertz

DIRECT- The higher the frequency, the more penetrating

the radiation.

Velocity definition

Speed of a wave

Which kind of radiation has limited penetrating power and are unsuitable for exposing dental radiographs

Soft radiation

What kind of radiation has great penetrating power

Hard radiation

What is the relationship between wavelength and frequency?


Long wavelength= low frequency, low energy (Less penetrating)

Short wavelength= high frequency, high energy (more penetrating)

What are the properties of x-rays? (9)

1. Invisible

2. Travel in straight lines

3. Travel at the speed of light

4. Have no mass or weight

5. No charge

6. Interact with matter causing ionization

7. can penetrate opaque tissues and structures

8. can affect photographic film emulsion (causing a latent image)

9. can affect biological tissue

Radiopaque looks like what on a radiograph

white or light gray on the radiograph

Bone and Enamel

Materials that are extremely dense and have high atomic weight will absorb more or less x-rays than materials that are thin with low atomic weight.

MORE x-rays are absorbed

Radiolucent -

Appears dark gray or black

pulp chambers, muscles and skin

General/ Bremsstrahlung Radiation is produced when?

high speed electrons are stopped or slowed down by the tungsten atoms of the dental x-ray tube

Characteristic Radiation is produced when?

bombarding electron from the tube filament collides with an orbiting K electron of the tungsten target.

At what kVp does an x-ray machine have to be at to produce characteristic radiation.

70 or above kVp

What are the 4 possible interactions of dental x-rays with matter?

No Interaction

Coherent scattering

photoelectric effect

Compton effect

No Interaction of dental x-rays with matter means what?

the x-ray can pass through an atom unchanged and no interaction occurs

Coherent Scattering of dental x-rays with matter means what?

(Unmodified scattering)

When a low energy x-ray passes near an atoms outer electron, it may be scattered without any loss of energy

Scattered= no loss of energy

Photoelectric effect of dental x-rays with matter means what?

This is an all or nothing energy loss

the dental x-ray simply vanishes because it was only made of energy

Compton Effect of dental x-rays with matter means what?

Only part of the dental x-ray energy is transferred to the electron and a new, weaker x-ray is formed and scattered in a new direction

Compton's effect accounts for what percent of interactions of matter with the dental x-ray beam?


The most widely accepted terms used for radiation units of measurements come from where?

systeme internationale (SI)

What are the systeme internationale units?

Columbus per kilogram (C/kg)

Gray (Gy)

Sievert (Sv)

What is the unit of measuring exposure?

Columbus per kilogram (C/kg)

What is the unit of measuring the absorbed dose?

Gray (Gy)

What is the unit of measuring dose equivalent?

Sievert (Sv)

the measurement of ionization in air produced by x or gamma rays is known as what?

Is Exposure

The amount of energy deposited in any form of matter (By any type of radiation)

Absorbed Dose

Product of the absorbed dose X a biological effect qualifying or weighting factor is known as?

Dose equivalent

To aid in making more accurate comparisons between different radiographic exposures. Is used to compare the risk of the radiation exposure producing a biological response is known as what?

Effective Dose Equivalent

What are the 3 basic building bocks of an atom?

Protons, neutrons, and electrons

Ionizing radiation is what?

any radiation that produces ions

Electromagnetic radiation has what properties of what?