Chapter One Radiation History ,chapter two radiation physics, chapter 3 radiation characteristics. Flashcards
Radiograph
A two dimensional representation of a three dimensional object. In practice, often called an X-ray This is not correct.
Radiation
A form of energy carried by waves or a stream of particles
Uses of dental radiographs
Detect lesions, confirm or classify suspected des ease, localize lesions or foreign object, provide information during dental procedures such as root canal therapy, placement of dental implants, illustrate changes secondary to caries, periodontal disease, and trauma, document the condition of a patient at a specific point in time, aid in development of a clinical treatment plan.
The history of dental radiography begins with the?
Discovery of x ray.
Who discovered the X-ray and when.
Wilhelmina Conrad roentgen , on November 8 1895
Who is credited with the first practical use of radiographs in dentistry? What year?
C. Edmund Kells 1896. He exposed the first radiograph in the United States using a living person.
Other pioneers in dental radiography?
William H Rollins , a Boston dentist who developed the first dental x ray unit.
The meaning of the term quality in dental radiography is used to
Discernible the mean energy or penetrating ability of the x ray beam.
Voltage is
A measurement of force that refers to the potential differences between two electrical charges.
Inside the dental X-ray tube head voltage is
The measurement of electrical force that causes electrons to move from the negative cathode to the positive anode.
Voltage determines
The speed of electrons that travel from cathode to anode.
When voltage is increased
The speed of electrons is increased.
1 kilovolt (kv) is equal to
1000 volts
Kilovoltage peak ( kvp )
Maximum or peak voltage
Increasing the kilovoltage peak results in
A higher energy X-ray beam with increased penetrating ability
Density
The overal blackness of an image.
An adjustment in kilovoltage peak results in.
Change in the density of the dental radiograph
When the kilovoltage peak is increased while other exsposire factors remain constant.
The result exhibits increased density and appears darker.
When low kilovoltage peak settings are used (65- 70)
A high contrast image will result.
A high contrast image
Lots of light lots of dark few gray
A image with high contrast is useful for detection and progression of dental carries.
True
Exposure time
Refers to the interval of time during which X-rays are produced.
Exposure time is measured in
Impulses
X-rays are created in a series of
Burst or pulses rather than a continuous stream.
One impulse occurs every
1/60 of a second ( 60 impulses a second)
Amperage determines
The amount of electrons passing through the cathode filament.
An increase in the number of electrons available to travel from the cathode to the anode results in?
Production of an increases number of X-rays
The quantity of the X-rays produced is controlled by
Milliamperage
Both milliamperes and exsposure time have a
Direct influence on the number of electrons produced by the cathode filament.
The product of milliamperes and exposure time is
Determined milliampere-seconds ( mAs)
Milliampere x exposure time (seconds) =
Milliampere-seconds
Intensity
The product of quantity(number of X-ray photons) and quality(energy of each photon) per unit of area per unit of time of exsposure.
Intensity of yhe X-ray beam is effected by a number of things such as
Kilovoltage peak, milliamperage, exsposure time and distance.
The inverse square law is used to
Explain how distance effects the intensity of the X-ray beam
The inverse square law
The intensity of radiation is universally proportional to the square of the distance from the source of radiation
As one variable increases the other is decreased this is called
Inversely proportional
Aluminum filters are placed in the path of the beam inside the dental X-ray tub head to ?
Reduce the intensity of the X-ray beam
Aluminum filters are used to remove
The lowenergy ,less penetrating , longer- wavelength X-rays.
Aluminum filters increase the
Mean penetrating capability of the X-ray beam while reducing the intensity.
Matter
Anything that occupies space and hasmass
When matter is altered
Energy results
The fundamental unit of matter is
The atom
Nucleus
Dense core of the atom
Nucleus is composed of
Protons and neutrons
Protons and neutrons are also known as
Nucleons
The number of protons inside the nucleus
Equals the number of electrons outside the nucleus and determines the atomic number of the atom.
Each atom has an
Atomic number
Hydrogen the simplistic atom has the atomic number of
1
Electrons
Are tiny negatively charged particles that have very little mass
Electrons Tavel around the nucleuse in path mown as
Orbits or shells
Shells are designed with the letters
K-Q, k being the closest to the nucleus and having the highest energy level.
Electrons are maintained in there orbits by
Electrostatic force
Electrostatic force
Attraction between the positive nucleus and negative electrons. This is known as BINDING ENERGY.
The binding energy is determined by
The distance between the nucleus and the orbiting electron and is different for each shell.
The strongest binding energy is found
Closest to the nucleus in the k shell.
If the atom has more electrons than protons and neutrons it has a
Negative charge.