Study Rad Technique 4.1-46 Flash Cards

 
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Rad Technique 4.1-46

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How are high speed electrons produced?
High potential differences (KV) applied across the tube.

WHICH

Gives filament very high negative charge

Gives anode an equally high positive charge.
High speed electrons projected in a stream from the heated cathode of a vacuum tube under the propulsion of a strong electric field
Cathode Ray
Material use as glass enclosure
Pyrex
Used for glass and glassware that contains appreciable Oxide of Boron and is resistant to heat chemicals and electricity
Pyrex
Substance or body capable of transmitting electricit, heat or sound
Conductor
Two types of Anode
Stationary
Rotating
Two components of an anode
Rotor located inside, made of copper and soft iron.

Stator located outside
What is the main purpose of the anode
To withstand high heat
The area of the target from which x-rays are emitted
Focal Spot
EFS
Effective focal spot size
Area projected onto the patient and the film
A gray white hard, brittle corrosion resistant metallic element used in high temperature. Structural materials and electrical elements
Tungsten
Stationary part of a machine such as a motor, about which a rotor turns
Stator
Common reddish metallic element that is ductile and malleable and one of the best conductors of heat and electricity
Copper
What is the purpose of the focusing cup
To focus the electron. Cause electron stream to converge onto the target anode
Two (2) components of a cathode
Filament
Focusing Cup
Metallic surface usually of platinum or tungsten upon which the stream of cathode rays within an x-ray tube is focused and from which the x-rays are emitted
Target
A cloud of electrons in the vicinity of the filament
Space Charge
Negatively charged metal shroud in which the filament is embedded
Focusing cup
A tenuous conductor made incandescent by the passage of an electric current
Filament
To tend or move toward one point or another
Converge
5 things that can happen with loss of vacuum
Electron flow is hinderd
Fewer x-rays produced
More heat generated
Uncontrolled secondary electrons
Wide variations in the tube current
The purpose of the pyrex glass envalope
Maintain vacuum
Melting Point of tungsten
3410 C
Components of X-ray tube
Cathode
Anode
Glass envelope
A shaft made of bars of copper and soft iron fabricated in one mass, located inside the x-ray glass envelope
Rotor
Electron emitting electrode of an electron tube
Cathode
Electron collecting electrode of an electron tube
Anode
The designs of modern X-ray tubes
Rotating Anode
Grid controlled (which equals 2kV)
Mammography tube - operated at low kV (less than 50kVp)
Disadvantage of Coolidge tube (hot cathode)
Independent control of kV and mA
Intensity and energy of X-ray beam can be selected separately with great accuracy
Characteristics of a Coolidge tube (hot cathode)
Compatible for use with Snook transformer
Vacuum tube allows intesnsity and energy to be selected seperatly and with great accuracy

Normally made of two electrodes (a diode) in a glass tube
Disadvantages of Crookes tube
Electron flow hindered
Fewer X-ray produced
More heat generated
An electron tube with an anode, a cathode and controlling grid
Triode
A metallic element that resembles chromium and tungsten in amny properties, is used especially in strengthening and hardening steel
Molybdenum
Negative potential across a triode of a grid controlled tube
Grid Bias
Large partially evacuated glass tube
Crookes Tube
A Vacuum X-ray tube which allowed x-ray intensity and energy to be selectred seperatly and with great accuracy
Coolidge Tube
A steel-grey, light wieght corrosion resistant, rigid, metallic element used chiefy as a hardening agent
Beryllium
% if heat produced in x-ray
99.4%
Four (4) conditions necessary for productions of x-rays
Seperation
Production
Focusing
Stopping
Principles of X-ray production
Rapid Deceleration
Cascade effect
An electrically charged particle emitted by an incandescent substance
Thermions
A low current of electricity which flows through the filament of the cathode
Fialment Current
White, glowing, or luminous with intense heat
Incandescent
Unveiled the hot cathode x-ray tube in 1913
William D Coolidge
Developed the Fluorescope and Fluorescence in 1898
Thomas Edison
Denonstrated technique of reducing exposure times and enhancing the image by using double emulsion radiography in 1904
Charles Leonard
Demonstrated the technique of reducing exposure times by using an intensifying screen in conjunction with glass photographic plates in 1896
Michael Pupin
Discoverd x-rays on Nov 8 1895
Roentgen
Developed large partially evacuated glass tube
William Crookes
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