X-ray Imaging System Ch 6 Flashcards
Three Principal Parts of X-ray Imaging System
X-ray Tube, Operating Console & High
Voltage Generator
It is attached to an overhead movable crane
assembly
Radiographic X-ray Tube
It is located under the examination table
Fluoroscopic X-ray Tube
It must be transparent to x-rays as possible
Examination Table
Fluoroscopic Table Tilt
Tilt: 90 to the foot/30 to the head
It is housed in an equipment cabinet
positioned against a wall
High Voltage Generator
It is used to control the x-ray tube current &
voltage applied to the x-ray tube
Operating Console
The intensity of the x-ray beam (mAs)
Radiation Quantity
The penetrability of the x-ray beam (kVp)
Radiation Quality
It measures the voltage provided to the x-ray
imaging system
Line Compensator
supplies a precise voltage to the
filament circuit & high-voltage circuit
Autotransformer
It conducts the input power to the
autotransformer
Primary Connection
It states that the voltage receive & provide
by the transformer is directly proportional to
the number of turns
Autotransformer Law
Autotransformer Law Formula
Vs/Vp = Ns/Np
Adjustment of Kilovoltage Peak (kVp)
Major & minor kVp
It determines the quality of the x-ray beam
kVp
It reads voltage (not kVp)
kVp Meter
It allows the voltage to be monitored before
an exposure
Prereading kVp Meter
It is measured in milliamperes
X-ray Tube Current
It determines the number of electrons
emitted by the filament
Filament Temperature
It controls the filament temperature
Filament Current
It controls x-ray tube current
Filament Circuit
A phenomenon of the space charge that
makes it difficult for subsequent electrons to
be emitted by the filament because of
electrostatic repulsion
Space Charge Effect
Electron cloud near the filament
Space Charge
The release of electrons from a heated
filament
Thermionic Emission
It is used to reduce the voltage to a value
that corresponds to the selected
milliamperage
Precision Resistor
Design in which exposure factors are
adjusted automatically to the highest mA at
the shortest exposure time allowed by the
high-voltage generator
Falling Load Generator
The product of x-ray tube current (mA) & exposure time (s)
mAs
It monitors the x-ray tube current
mA Meter
It terminates an exposure after a prescribed
time (6 s)
Guard Timer
It consists of an electronic device
Timer Circuit
Four Types of Timing Circuits
Synchronous Timer, Electronic Timer, mAs
Timer & Automatic Exposure Control
A precision device designed to drive a shaft
at precisely 60 revolution per second
Synchronous Timer
Most sophisticated, most complicated & most accurate (as small as 1 ms)
Electronic Timer
Most exposure timers are electronic & are
controlled by a…
microprocessor
A device that measure the quantity of
radiation that reaches the image receptor
Automatic Exposure Control (AEC)
It is used to check timer accuracy (as short
as 1 ms)
Solid-state Detectors
It increases the output voltage from the
autotransformer to the kVp necessary for xray production
High Voltage Generator
Three Primary Parts if Generator
High Voltage Transformer, Filament
Transformer & Rectifiers
The ratio of the number of secondary
windings to the number of primary windings
Turns Ratio
It ensures that electrons flow from cathode
to anode only
Voltage Rectification
The process of converting alternating
current (AC) to direct current (DC)
Rectification
An electronic device that allows current
flow in only one direction
Rectifier
An electronic device that contains two
electrodes
Diode
It replaced by solid-state rectifier
Valve Tube
2 types of Semiconductor
P-type and n-type
The voltage is not allowed to swing
negatively during the negative half of its
cycle
Half-Wave Rectification
The negative half-cycle corresponding to the
inverse voltage is reverse
Full-Wave Rectification
It results in a pulsating x-ray beam
Single-Phase Power
The voltage impressed across the x-ray tube
is nearly constant
Three-Phase Power
Starting an exposure
Initiation Time
Ending an exposure
Extinction Time
It produces a nearly constant potential
voltage waveform
High Frequency Generator
A high-speed switchers or choppers that
convert DC into a series of square pulses
Inverter Circuit
LTube voltage falls during exposure
Capacitor Discharge Generator
An automatic lead beam stopper
Grid-Controlled X-ray Tube
