Chapter 6 Flashcards
What are the two types of X-ray equipment?
Diagnostic and Therapeutic
Diagnostic ranges: 10–1200 milliamperes (mA), 0.001–10 seconds, 25–150 kilovoltage peak (kVp). Therapeutic includes radiation oncology capable of x-ray and electron therapy.
What is the purpose of a Bucky tray on an X-ray table?
To hold the image receptor and assist in image capturing
It is designed to provide a uniform, radiolucent surface that is easy to clean and free of crevices.
What are the characteristics of incoming line current in the United States?
60 Hz cycle, 220–240 V
Worldwide, the frequency is typically 50 cycles.
What is the main difference between single-phase and three-phase power?
Single-phase is inefficient and has 100% voltage ripple; three-phase is more efficient with low voltage ripple
Three-phase power is the most popular and widely available for x-ray machines.
What is a deadman switch in the context of X-ray equipment?
A switch that must be continuously pressed to maintain the exposure
Located behind the control window on the generator console.
Fill in the blank: The _______ circuit regulates exposure termination in X-ray equipment.
Timer
Timer circuits can be electronic or milliampere-second (mAs) timers.
What does the term ‘voltage ripple’ refer to?
The fluctuation in voltage output of the generator
It indicates the stability and efficiency of the power supply.
True or False: High-frequency generators produce a voltage ripple of 3-4 percent.
True
High-frequency generators are considered the most efficient for x-ray production.
What is the purpose of a capacitor discharge mobile unit?
To provide a portable power source for x-ray imaging
It requires precharging a large electrical capacitor and delivers lower rms voltage.
What type of AEC technology is most commonly used?
Ionization chambers
Ionization chambers are located in front of the image receptor and typically have three detector positions.
What is the minimum reaction time for modern AEC systems?
0.001 seconds
This utilizes solid-state switching (SCR) technology.
What is the function of backup time in AEC systems?
To protect the patient and equipment from overexposure
It is often set at 150% of the anticipated manual technique.
What does the power rating of an X-ray generator indicate?
The greatest load the generator can apply to the tube
Calculated by the formula V × A = W and expressed in kilowatts (kW).
Fill in the blank: The _______ circuit provides current and voltage to the filament in an X-ray tube.
Filament
This circuit allows for the selection of milli-amperage (mA).
What are the pulse characteristics of single-phase generators?
2 pulses per Hz, 120 pulses per second
Voltage ripple is 100 percent.
What is the voltage ripple percentage for 12-pulse three-phase generators?
4-10 percent
This indicates a more stable and efficient output compared to single-phase generators.
What is the main advantage of battery-operated mobile units?
They provide portable radiography capabilities
They are equipped with rechargeable batteries and supply nonpulsating direct current.
How many alterations in the direction of the current flow occur in 0.10 second in a 60 Hz AC current?
12
Where in the x-ray circuit is the rectification circuit located?
between the step-up transformer and the x-ray tube
Where is the stator of the anode induction motor located?
outside the glass envelope and outside the rotor
Where is exposure switch found
between the autotransformer and the timer circuit.
What is the electrical device used to adjust the mA selection
variable resistor
In the x-ray circuit, the timing control is found between the
incoming line and the step-down transformer
In the x-ray circuit, the mA control is found between the
incoming line and the step-down transformer
In the x-ray circuit, kVp control is found between the
incoming line and the exposure switch
What control is not operator dependent?
rotor speed
The time interval for an AEC detector to sense the presence of radiation and terminate the exposure is referred to as
minimum reaction time
Radiographic rooms equipped with a tilting table are primarily designed for performing ____ procedures.
fluoroscopic
Which tube suspension system offers the greatest multidirectional movement?
overhead tube suspension system
Nearly all types of x-ray equipment operate from an incoming line of
210 V
The three main parts of the x-ray imaging system are the x-ray tube, ____________, and ____________.
operating console, high voltage generator
How many windings does the autotransformer have?
one
A step-down transformer is located in the _______ circuit.
filament
The high voltage generator contains the high voltage transformer, the __________, and the ___________.
filament transformer, rectifiers
In modern imaging systems, the components for rectification are ____________.
solid state semiconductors
Full-wave rectified, three-phase units provide an x-ray beam at _____ pulse(es) per second.
360
Voltage across the x-ray tube is most constant with _________________.
high frequency generators
When using AEC at 80 KVp, backup times
must not exceed 600 mAs
What does automatic exposure control technology determine
exposure time
