DADDY Flashcards
dThree Principal Parts of X-ray Imaging System
X-ray Tube, Operating Console & High Voltage Generator
It is attached to an overhead movable crane assembly
X-ray Tube
LOCATIONOF X-RAY TUBE
examination room
Fluoroscopic X-ray Tube is located____
under the examination table
Examination Table must be ____
transparent to x-rays as possible
composition of examination table
carbon fiber
ratio of Fluoroscopic Table Tilt
90/30
90 degree to foot side
30 to head side
housed in an equipment cabinet positioned against a wall
High Voltage Generator
High Voltage Generator is always clodes to the
x-ray tube
Most familiar to the radiologic technologist
Operating Console
It is used to control the x-ray tube current & voltage applied to the x-ray tube
Operating Console
It provides control of line compensation, kVp, mA & exposure time
Operating Console
The number of x-rays
Radiation Quantity
The intensity of the x-ray beam
Radiation Quantity
Radiation Quantity units
mR or mR/mAs
The penetrability of the x-ray beam
radiation quality
radiation quality is expressed in
kvp or hvl
It measures the voltage provided to the x-ray imaging system
Line Compensator
It controls the kVp
Autotransformer
It consists of only one winding of wire & one core
Autotransformer
supplies a precise voltage to the filament circuit & high-voltage circuit
Autotransformer
location of autotransformer
operating console
Autotransformer Law
states that the voltage receive & provide by the transformer is directly proportional to the number of turns
formula of autotransformer law
Formula: Vs/Vp = Ns/Np
It conducts the input power to the autotransformer
Primary Connection
Adjustment of Kilovoltage Peak (kVp)
Major & minor kVp
It reads voltage (not kVp)
kVp Meter
It determines the quality of the x-ray beam
kVp
Location: output terminals of the autotransformer
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 is measured in amperes
Filament Current
Filament Current range from___ to __
3-6 A
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
Three Main Section of X-ray Imaging System
X-ray tube, Operating Console & High-Voltage
Power Rating (kW) formula for three-phase and high frequenc
(mA x kVp)/1000
Power Rating (kW) formula for single-phase
(0.7)(mA x kVp)/1000
Fewer low-energy projectile electrons pass from cathode to anode
Greater radiation quality
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
The product of x-ray tube current (mA) & exposure time (s)
mAs
It monitors the x-ray tube current
mA Meter
Filament Transformer
Full Name
Filament Heating Isolation Step-down Transformer
Primary windings
o Thin copper
o Current: 0.5-1 A
o Voltage: 150 V
Secondary windings:
o Thick
o Current: 5-8 A
o Voltage: 12 V
It terminates an exposure after a prescribed time (6 s)
Guard Timer
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
It cannot be used for serial exposures
Synchronous Timer
Most sophisticated, most complicated & most accurate (as small as 1 ms)
Electronic Timer
It is used to check timer accuracy (as short as 1 ms)
Solid-state Detectors
Terminates exposure when desired mAs value is attained
mAs Timer
A device that measure the quantity of radiation that reaches the image receptor
Automatic Exposure Control (AEC)
It increases the output voltage from the autotransformer to the kVp necessary for x-ray production
High Voltage Generator
Three Primary Parts of high voltage generator
High Voltage Transformer, Filament Transformer & Rectifiers
A step-up transformer
High Voltage Transformer
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
Have loosely bound electrons (free to move)
Have spaces called holes (no electrons)
P-type Semiconductor
The voltage is not allowed to swing negatively during the negative half of its cycle
Half-Wave Rectification
It produces a nearly constant potential voltage waveform
High Frequency Generator
The voltage impressed across the x-ray tube is nearly constant
6 pulses/1/60 second
Three-Phase Power
The negative half-cycle corresponding to the inverse voltage is reverse
Full-Wave Rectification
Tube voltage falls during exposure
Approximately 1 kV/mAs
Capacitor Discharge Generator
