All of the following are associated with the anode...
-the focal track
-the heel effect
-the line focus principle
The type of x-ray tube designed to turn on and off rapidly, providing multiple short, precise exposures, is
Which of the following circuit devices operate(s) on the principle of self-induction?
If exposure factors of 85 kV, 400 mA, and 12 ms yield an output exposure of 150 mR, what is the milliroentgens per millampereseconds (mR/mAs)?
If a high-voltag transformer has primary turns and 50,000 secondary turns and i supplied by 220 V and 100 A, what are the secondary voltage current?
200 mA and 110 kV
The minimum response time of an automatic exposure control (AEC)
is the shortest possible exposure time
Which of the following causes pitting, or many small surface melts, of the anode's focal track?
repeated, frequent overloading
Which of the following is (are) characteristics of the x-ray tube?
-the target material should have a high atomic number and a high melting point
-the useful beam emerges from the port window
-the cathode assembly recieves both low and high voltages
A parallel-plate ionization chamber recieves a particular charge as x-ray photons travel through it. This is the operating principle of which of the following devices?
Which of the following will serve to increase the effective energy of the x-ray beam?
-increase in added filtration
-increase in kilovoltage
Which of the following combinations would pose the least hazard to a particular anode?
1.2 mm focal spot, 92 kV, 1.5 mAs
Delivery of a large exposures to a cold anode or the use of exposures exceeding tube limitation can result in
-cracking of the anode
If the primary coil of a high-voltage transformer is supplied by 220 V and has 400 turns and the secondary coil has 100,000 turns, what is the voltage induced in the secondary coil
Which of the following is/are components of the secondary, or high voltage, side of the x-ray circuit?
Patient dose during fluoroscopy is affected by
-distance between the patient and the input phosphor
-amount of magnification
A back-up timer for the AEC serves to
-protect the patient from overexposure
-protect the x-ray tube from excessive heat
the essential function of a phototimer is to
terminate the x-ray exposure once the IR is correctly exposed
In which of the following examinations would an IP front with very low absorption properties be especially important?
Which of the will improve the spatial resolution of image intensified images?
-a very thin coating of cesium iodide on the input phosphor
-a smaller diameter input screen
The advantages of collimators over aperature diaphragms and flare cones include
-the variety of field sizes avaliable
-mire efficient beam restriction
Which of the following occurs during Bremsstrahlung (brems) radiation production?
an electron makes a transition from an outer to an inner electron shell
Characteristics of the metallic element tungsten include
-ready dissipation of heat
-high melting point
-high atomic number
the device that recieves the remnant beam, converts it into light, and then increases the brightness of that light is the
A high speed electron entering the tungsten target is attracted to the positive nucleus of a tungsten atom and, in the process, is decelerated. This results in
All of the following are components of the image intensifier
Components of digital imaging include
-computer manipulation of the image
-formation of an electronic image on the radiation detector
Which of the following is used in digital fluoroscopy, replacing the image intensifier's television camera tube?
A three-phase timer can be tested for accuracy using a synchronous spinning top. The resulting image looks like a
solid arc, with rhe angle (in degrees) representative of the exposure time
the regular measurement and evaluation of radiographic equipment components and their performance is most accurately termed as
the procedure whose basic operation involves reciprocal motion of the x-ray tube and film is
In fluoroscopy, the automatic brightness control is used to adjust the
kilovoltage (kV) and milliamperage (mA)
When the radiographer selects kilovoltage on the control panel, which device is adjusted?
What is the device that directs the light emitted from the image intensifier to various viewing and imaging apparatus?
As electrons impinge on the anode surface, less than 1% of their kinetic energy is changed to
Which of the following contribute(s) to inherent filtration?
-x-ray tube glass envelope
-x-ray tube port window
A quality-control (QC) program includes checks on which of the following radiographic equipment conditions?
-positive beam limitation/autmatic collimation
Characteristics of x-ray photons include
-a penetrating effect on all matter
-an ionizing effect on air
All the following x-ray circuit devices are located between the incoming power supply and the primary coil of the high voltage transformer
-the kilovoltage meter
Which of the following systems function(s) to compensate for changing patient/part thicknesses during fluoroscopic procedures?
automatic brightness control
Disadvantages of moving grids over stationary grids include which of the following?
-they can prohibit the use of very short exposure times
-they increase patient radiation dose
The functions of a picture archiving and communication system (PACS) include
-acquisition of digital images
-storage of digital images
How many half value layers will it take to reduce an x-ray beam whose intensity is 78 R/min to an intensity of less than 10 R/min?
The kV setting on radiographic equipment must be tested annually and must be accurate to within
An incorrect relationship between the primary beam and the center of a focused grid results in
-grid cut off
-insufficient radiographic density
Conditions that contribute to x-ray tube damage include
-lengthy anode rotation
-exposures to a cold anode
Which of the following information is necessary to determine the maximum safe kilovoltage using the appropriate x-ray tube rating chart?
-milliamperage and exposure time
-focal spot size
A device used to ensure reproducibility radiographs, regardless of tissue-density variations, is the
automatic exposure control
If the distance from the focal spot to the center of the collimators mirror is 6 in., what distance should the illuminator's light bulb be from the center of the mirror?
To maintain image clarity in an image intensifier system, the path of electron flow from the photocathode to the output phosphor is controlled by
Deposition of vaporized tungsten on the inner surface of the x-ray tube glass window
acts as additional filtration
design characteristics of x-ray tube targets that determine heat capacity include the
-rotation of the anode
-diameter of the anode
-size of the focal spot
the brightness level of the fluoroscopic image can vary with
Which of the following is the correct formula for determining heat units for a three phase 12 pulse x-ray machine?
mA X time X kV X 1.41
Component parts of a CT imaging system include a(n)
-high frequency generator
With what frequency must radiographic equipment be checked for linearity and reproducibility?
a technique chart should be prepared for each AEC x-ray unit and should contain which of the following information for each type of examination?
Moving the image intensifier closer to the patient during fluoroscopy
-decreases the SID
-decreases patient dose
-improves image quality
If a radiogrph exposed using an AEC is over exposed becuase an exposure shorter than the minimum response time was required, the radiographer generally should
decrease the milliamperage
Exposures less than the minimum response time of an AEC may be required when
-using high milliamperage
-using fast film-screen combinations
Which of the following is/are associated with magnification fluroscopy?
-higher patient dose than nonmagnification fluoroscopy
-higher voltage to the focusing lens
-image intensifier focal point closer to the input phosphor
Advantages of battery-powered mobile x-ray units include their
-ability to store a large quantity of energy
-ability to store energy for extended periods of time
Which of the following modes of a trifield image intensifier will result in the highest patient dose?
its 12 in mode
Off focus or extrafocal, radiation is minimized by
restricting the x-ray beam as close to its source as possible
An AEC device can operate on which of the following principles?
-a photomultiplier tube charged by a fluororecent screen
-a parallel plate ionization chamber charged by x-ray photons
If 92 kV and 15 mAs were used for a particular abdominal exposure with single phase equipment, what milliampere-seconds calue would be required to produce a similar radiograph with three phase 12 pulse equipment?
Fractional focus tubes with a 0.3 mm focal spot or smaller, have special application in
referring to the anode cooling chart in the figure if the anode is saturated with 300,000 heat units (HU) how long will the anode to cool before another 160,000 HU can be safely applied?
Anode angle will have an effect on the
-severity of the heel effect
-focal spot size
-heat load capacity
Which of the following devices is (are) component(s) of a typical fluoroscopic video display system?
Which of the following formulas would the radiographer use to determine the total number of heat units produced with a given exposure using three-phase, six pulse equipment?
mA X time X kV X 1.35
With three-phase equipment the voltage across the x-ray tube
-is 87% to 96% of the maximum value
-is at nearly constant potential
Radiographs from a particular single phase full wave rectified x-ray unit were overexposed using known correct exposures. A spinning top test was performed at 200 mA, 0.05 sec, and 70 kV, and 8 dots were visualizedon the finished film. which of the following is indicated?
the 0.05 sec time station is inaccurate
Which of the following combinations will offer the greatest heat loading capabilit?
10 degree target angle, 1.2 mm actual focal spot
The filtering effect of the x-ray tubes glass envelope and its coolant are referred to collectively as
accurate operation of the AEC device depends on
-positioning of the object with respect to the photocell
the total number of x-ray photons produced at the target is contingent on the
-square of the kilovoltage
x-ray tubes used in CT imaging systems must be capable of
-high short exposure rating
-tolerating millions of heat units
-high speed anode rotation
QA was being performed on a three-phase full wave rectified x-ray unit. a synchronous spinning top test was performed using 300 mA, 60 ms, and 70 kV, and a 22 degree arc was observed on the test film. which of the following is most correct about the results?
the test results are satisfactory