Chapter 3: Equipment Operation and Quality Control (Review)
Which of the following statements are false? 1. A magnetic field always surrounds an electrical charge in motion 2. Current flows back and forth in AC 3. Current flows in one direction in DC 4. The volt is the unit of electrical current 5. A conductor allows the free flow of electrons 6. The ampere is the unit of electromotive force 7. The volt is the unit of potential difference 8. The path of electrical current is called the circuit 9. Ohm's law is calculated using the equation VI = R 10. A semiconductor is a material that may act as a conductor under some conditions and as an insulator under other conditions a. 4, 6, 9 b. 1, 2, 3, 5, 7, 8, 10 c. 1, 7, 10 d. 4, 6, 9, 10
A. Keep in mind that the question asks for which statements are false. Choice 4 is false because the ampere is the unit of electric current. Choice 6 is false because the volt is the unit of electromotive force choice 9 is false because Ohm's law is calculated by use of the equation V/IR. This question is a bit long, and you probably won't encounter one this complex. However, it is one more practice with a question of this type. Again, just treat it like a long true-false question.
The primary purpose of filtration is: a. Radiation protection b. Removal of short-wavelength (soft) rays c. Hardening the beam for imaging d. Removal of long-wavelength (hard) rays
A. Choice B is incorrect because soft rays have long wavelengths. Choice C is true, but it is not the primary purpose of filtration. Choice D is incorrect because long-wavelength rays are called soft rays.
Three-phase, 6-pulse full-wave rectification produces: a. Direct current with 13% ripple b. Direct current with 4% ripple c. Direct current with 100% ripple d. Alternating current with 13% ripple
A. 13% ripple direct current, not alternating current. Three-phase, 12-pulse produces ripple as low as 4%. Single-phase ripple is 100%.
The electricity provided to the radiology department operates at: a. 120 pulses per second b. 60 pulses per second c. 110 pulses per second d. 220 pulses per second
A. 60 cycles per second results in 120 pulses per second, because it cycles back and forth 120 times per second.
A step-down transformer: a. Steps down voltage b. Steps down current c. Steps up voltage d. Steps up resistance
A. A transformer is named for what it does to voltage.
X-rays are produced as incident electrons interact with inner shell electrons in target atoms by a process called: a. Characteristic b. Photoelectric c. Bremsstrahlung d. Compton
A. As incident electrons dislodge K-shell electrons in the target material, outer-shell electrons fall inward to fill the holes. This causes the release of energy in the form of x-rays, with energy characteristic of the difference in energy levels between the K-shell and L-shell.
What is atomic mass? a. The number of protons plus the number of neutrons b. The number of photons c. The number of electrons d. The number of protons plus the number of electrons
A. Atomic number is the number of protons. Protons and neutrons are contained in the atomic nucleus.
The test that measures the accuracy of successive exposures is: a. Exposure reproducibility b. Spinning top test c. Pinhole camera d. Exposure linearity
A. Be sure to review these quality control standards before you take the certification exam.
kVp must be accurate to within: a. 4 b. 5% c. 2% of SID d. 10%
A. Be sure to review these quality control standards before you take the certification exam.
Electromagnetic radiation travels: a. In waves along a straight path b. In circles c. Back and forth d. As electrons in waves along a straight path
A. Because it has mass, particulate radiation may travel along different paths.
What device spins at 3300 to 10,000 rpm? a. Anode b. mA meter c. Ionization chamber d. Step-up transformer
A. High-speed anodes spin from 10,000 to 12,0 rotations per minute (rpm).
What device is turned by a rotor? a. Anode b. mA meter c. Ionization chamber d. Step-up transformer
A. Pressing the rotor button activates a motor turns the anode. It also begins thermionic emission at the cathode.
Effective quality control and quality assurance programs are required for accreditation by: a. The Joint Commission b. Joint Review Committee on Education in Radiologic Technology c. American Healthcare Radiology Administrators d. Starfleet Academy
A. Representatives of The Joint Commission (TJC) regularly visit health care facilities to examine documentation of compliance with quality control and quality assurance standards.
The filament is kept warm by: a. A standby current from the time the x-ray machine is turned on b. Insulating oil c. Lead housing d. Current produced only during exposures
A. The machine keeps the filament warm be exposures.
Which device reduces voltage and provides current to produce an electron cloud or space charge at the filament? a. Step-down transformer b. Rectifier c. Cathode d. Timer
A. The step-down transformer is located in the filament circuit.
What is the source of bremsstrahlung and characteristic rays? a. Anode b. mA meter c. Falling load generator d. Step-up transformer
A. These are the x-rays produced by two types of interactions that occur between incident electrons from cathode and the tungsten atoms of the anode.
Total brightness gain achieved using an image intensifier equals: a. Flux gain times minification gain b. Diameter of input phosphor times diameter of output phosphor c. Intensification factor—brightness without an image intensifier divided by brightness with an image intensifier d. Total light emitted at the photocathode
A. This is the equation used to calculate total brightness gain.
The electron stream passes from cathode to anode because of passing through the x-ray tube. a. Current b. Kilovoltage c. Tungsten d. Heat
A. This is the flow of electrons, as a result of AC being changed to DC in the rectifier.
The portion of the image-intensifier tube that converts electron energy to visible light is the: a. Output phosphor b. Photocathode c. Input phosphor d. Brightness gain
A. This is where the electronic image again becomes visible.
What type of current is required for proper operation of the x-ray tube? a. Direct b. Falling load c. Alternating d. Fluctuating
A. This necessitates the using of a rectifier to change AC to DC.
AECs may be tested using: a. Phantoms b. Images of real patients c. Analog meters d. Fluoroscopic screens
A. This provides for actually radiographing an object.
A transformer that has more turns in the secondary coil than in the primary coil is called a: a. Step-up transformer b. Solenoid c. Step-down transformer d. Filament transformer
A. Voltage is stepped up while current is stepped down in the same proportion. A transformer is named for what it does to voltage.
Waves of radiation are called: a. Sine waves b. Strong waves c. Signal waves d. Current waves
A. Wavelength and frequency are inverse to one another.
Which of the following are properties of x-rays? 1. Electrically negative 2. Affect film emulsion 3. Scatter and produce secondary radiation 4. Invisible to the human eye 5. Travel at the speed of light (186,000 miles per hour) 6. Possess wavelengths between 1 A and S A 7. Travel in bundles of energy called photons 8. Can ionize matter and gases 9. Can be focused by collimators 10. Cause phosphors to fluoresce a. 2, 3, 7, 8 b. 2, 3, 4, 7, 8, 10 c. 1, 5, 6, 9 d. 2, 3,4,6, 8, 9, 10
B. Choice 1 is incorrect because x-rays do not carry electrical charges. Choice 5 is incorrect because the speed of light is 186,000 miles per second. Choice 6 is incorrect because the wavelengths of x-rays are between 0.1 and 0.5 angstroms. Choice 9 is incorrect because x-rays cannot be focused by any means. Collimation merely restricts the area being irradiated. Again, you are not likely to encounter such a long question on the exam, but this question provides a good review of the properties of x-rays. Don't be intimidated by slight changes in question format. Always read the question carefully, determine what is being asked, and read each choice carefully to determine the correct answer. When you have mastered that, you can answer any question that pops up on the screen.
Which of the following statements are true regarding electrostatic charges? 1. Electrostatics is the study of electric charges at rest 2. The movement of electrons from one object to another is called ionization 3. Like charges attract, and unlike charges repel 4. Electrostatic charges concentrate on a conductor in the area of greatest curvature 5. Friction, contact, and induction are methods of ionization a. 2, 3, 5 b. 1, 4 c. 1,2,3 d. 2,4,5
B. Choice 2 cannot be the answer because the movement of electrons from one object to another is called electrification. Choice 3 cannot be the answer because like charges repel and unlike charges attract. Choice 5 cannot be the answer because friction, contact, and induction are methods of electrification. You may encounter some questions in this format. Simply make each possible choice a true-false statement, then choose the one answer that includes the true choices. These are not difficult questions, just challenging.
What is located in the x-ray circuit between the high-voltage transformer and the x-ray tube? a. Step-down transformer b. Rectifier c. Cathode d. Timer
B. At this point, AC is changed to DC so that current is flowing in only one direction through the x-ray, tube.
The x-ray beam changes as it travels through the patient by a process called: a. Filtration b. Attenuation c. Electrification d. Annihilation
B. Attenuation means that the x-rays may be absorbed or scattered.
Exposure reproducibility must be accurate to within: a. 4 b. 5% c. 2% of SID d. 10%
B. Be sure to review these quality control standards before you take the certification exam.
When making an exposure, the radiographer should: a. Hold the rotor for several seconds before pressing "expose" b. Activate the rotor and exposure switch in one continuous motion c. Begin the rotor while a student is still positioning the patient d. Activate the rotor while estimating how fast the anode is spinning
B. Choice C is incorrect, although many first-year students experience this activity when technologists try to hurry them from the room! Choices A and D are incorrect because unnecessarily heating the filament actually reduces x-ray tube life.
Which of the following measures tube current? a. Anode b. mA meter c. Ionization chamber d. Falling load generator
B. Current is the flow of electrons, as measured ml milliamperes (mA). Hence the mA meter provides the reading.
Activating the rotor: a. Accelerates a procedure b. Reduces tube life c. Keeps it oiled d. Keeps the cooling fan activated
B. Each time the rotor is activated, thermionic emission begins to occur at the filament. This heating of the filament causes tungsten to evaporate, slowly deteriorating the filament.
Frequency is defined as: a. Synonymous with wavelength b. The number of waves passing a point per unit time c. The number of waves striking the patient d. The number of exposures needed during an examination
B. Higher-frequency waves have shorter wavelengths, lower-frequency waves have longer wavelengths.
Wavelength and frequency are: a. Directly proportional to each other b. Inversely proportional to each other c. Inversely proportional to the square of their distance d. Unrelated to each other
B. Higher-frequency waves have shorter wavelengths, lower-frequency waves have longer wavelengths.
In many cases, digital fluoroscopy eliminates which of the following? a. The need for a radiographer b. Postprocedure "overhead" images c. Image acquisition d. Accurate positioning
B. Most views required by the radiologist are acquired digitally during fluoroscopy.
Self-induction is used in the operation of what device? a. Step-up transformer b. Autotransformer c. Step-down transformer d. Electronic timer
B. Mutual induction occurs in the step-up and step-down transformers.
The amount of mA used for fluoroscopy is: a. 300 to 500 b. 3 to 5 c. 10 to 12 d. 100 to 300
B. Note that this question is asking the amount of mA actually used and not the setting of the mA on the control panel.
Examples of particulate radiation are: a. X-rays, gamma rays, and cosmic rays b. Helium nuclei and beta particles c. Electrons, protons, and meteorites d. X-rays and quarks
B. Particulate radiations are highly ionizing.
The two types of electromagnetic induction are: a. Autoinduction and mutual induction b. Self-induction and mutual induction c. Generated induction and self-induction d. Current induction and voltage induction
B. Self-induction occurs in the autotransformer; mutual induction occurs in the step-up and step-down transformers.
High-frequency power: a. Is less effective than single-phase power b. Has almost no ripple c. Has more ripple than three-phase power d. Is yet unproved
B. Such a low ripple means higher average photon energy. High frequency is very efficient.
What is the smallest particle of an element that retains the characteristics of the element? a. Mole b. Atom c. Molecule d. Quark
B. The atom may be broken down into subatomic particles but they would not have the characteristics of the element.
A variable transformer that is used to select kVp for the x-ray circuit is the: a. Step-up transformer b. Autotransformer c. Step-down transformer d. Rectifier
B. The autotransformer is a variable transformer that operates on the principle of self-induction.
The portion of the image-intensifier tube that converts visible light to an electronic image is the: a. Output phosphor b. Photocathode c. Input phosphor d. Brightness gain
B. The electrons are then concentrated and accelerated toward the output phosphor.
The law stating that the outer shell of an atom can contain no more than eight electrons is called: a. Ohm's law b. Octet rule c. Octagon rule d. Electron binding energy
B. The octet rule states that no more than eight electrons can be in the outer shell. It does not stipulate that there must be eight electrons in the outer shell.
Which of the following is composed of solid-state, silicon-based diodes? a. Step-down transformer b. Rectifier c. Cathode d. Timer
B. The rectifier changes AC to DC.
What changes AC to DC? a. Step-down transformer b. Rectifier c. Cathode d. Timer
B. The rectifier changes incoming alternating current from the power company into direct current for use by the x-ray tube.
The strength of the magnetic fields in a transformer is increased by: a. Coiling the wires and placing them in adjoining machines b. Coiling the wires and letting their magnetic fields overlap c. Keeping the wires very straight, increasing their effectiveness d. Replacing the wires with diodes
B. This intensifies the magnetic fields, making the transformers more efficient.
Heat is produced in the x-ray tube as: a. Electrons break apart while striking the anode b. Electrons interact with the target material c. The anode stops spinning d. The rectifier operates
B. This is primarily a result of bremsstrahlung interactions at the anode.
The increase in average photon energy when using three-phase, 12-pulse equipment compared with single-phase equipment is: a. 1.35% b. 41% c. 1.41% d. 35%
B. This is why the formula for calculating heat units for three-phase, 12-pulse equipment is multiplied by 1.41.
Three-phase, 12-pulse full-wave rectification produces: a. Direct current with 13% ripple b. Direct current with 4% ripple c. Direct current with 100% ripple d. Alternating current with 13% ripple
B. Three-phase, six-pulse produces ripple as low as 13%. Single-phase ripple is 100%.
The amount of material needed to reduce the intensity of the beam by ¹/₁₀ is called: a. Half-value layer b. Tenth-value layer c. Total filtration d. Inherent filtration
B. We more commonly discuss beam quality using the term half-value layer. Regardless of the fraction, it is always the amount of material needed to reduce beam intensity to that level.
The x-ray emission spectrum consists of: a. Brems and characteristic rays b. Discrete spectrum (produced by brems rays) and continuous spectrum (produced by characteristic rays) c. Discrete spectrum (produced by characteristic rays) and continuous spectrum (produced by brems rays) d. X-rays and electrons, both part of the electromagnetic spectrum
C.
The electricity provided to the radiology department is: a. 110 Hz or 220 Hz DC b. 110 Hz or 220 Hz DC c. 60 Hz; AC d. 60 Hz DC
C. 60 Hertz means 60 cycles per second. The voltage may be 110 or 220.
Electricity is supplied to the imaging department by a: a. Motor b. Rectifier c. Generator d. Voltmeter
C. A generator at the power company converts mechanical energy to electrical energy. A motor converts electrical energy to mechanical energy.
When a spinning top test is performed on single phase equipment, a radiograph exhibiting four dots would indicate: a. An accurate timer, if set on ½₀ second b. A malfunctioning timer, if set on ¹/₃ second c. An accurate timer, if set on ¹/₃₀ second d. b and c
C. An exposure of 1 second would demonstrate 120 dots, because single-phase, full-rectified units pulse every ¹/₁₂₀ second. An exposure of ¹/₃₀ second should demonstrate 4 dots (120 times 1/30) if it is working properly.
X-rays are produced as incident electrons interact with target atoms by a process called: a. Classical b. Photoelectric c. Bremsstrahlung d. Compton
C. As incident electrons fly past the atomic nuclei, they are slowed, causing the production of heat and x-rays by bremsstrahlung. X-rays are also produced by the characteristic interaction.
The intensity of radiation is inversely proportional to the square of the distance between the source of radiation and the person receiving it. This describes the: a. Square law b. Reciprocity law c. Inverse square law d. Octet law
C. Be certain to review the inverse square law; always remember the inverse square relationship. For example, if the dose of radiation is 10 R at a distance of 3 feet, the dose at a distance of 6 feet is only 2.5 R. It is one fourth, not half, which is a common mistake.
Resolution of the television system may be measured using the following tool(s): a. Wire mesh test b. Line pairs-per-millimeter resolution tool c. Resolution test pattern d. All of the above
C. Be sure to review these quality control standards before you take the certification exam.
The collimator must be accurate to a level of: a. 4 b. 5% c. 2% of SID d. 10%
C. Be sure to review these quality control standards before you take the certification exam.
Marks on the focal track of the anode resulting from bombardment of electrons are called: a. Melts b. Bullet marks c. Pitting d. Cracks
C. Choices A, B, and D are also marks on the focal track, but they are caused by malfunctions.
At what speed do x-rays travel? a. The speed of light-186,000 miles per hour b. The speed of the incident electrons-93,000 miles per second c. The speed of light-186,000 miles per second d. Infinite speed
C. Don't be fooled by choices that use different units of measurement. Light speed is expressed in miles per second, not miles per hour.
As radiation strikes matter: a. The energy of the rays is destroyed b. The energy of the rays is increased as they acquire the energy of the atoms c. The energy is transferred to the atoms according to the law of conservation of energy d. The energy is converted to matter according to Einstein's theory
C. Energy cannot be created or destroyed, only changed in form. The energy is merely transferred.
When a spinning top test is performed on three-phase equipment, a timer setting of ¹/₆₀ second should indicate the following on the resultant radiograph: a. 2 dots b. 60 dots c. 6-degree arc d. 90-degree arc
C. Keep in mind that because the current never falls to zero when three-phase equipment is used, a spin-fling top test will not show dots but will show arcs. A 1-second exposure would be expected to produce a full circle, which would be an arc of 360 degrees. A timer setting of ¹/₆₀ second would be expected to produce a ¹/₆₀-degree arc, which is a 6-degree arc (360 times ¹/₆₀) Choices A and B would be incorrect because they indicate dots. Choice D is incorrect.
What percentage of energy in the x-ray tube is converted to x-rays? a. 99% b. 75% c. 1% d. 100%
C. More than 99% of the energy is converted to heat.
What device may be used to ensure consistency of radiographic quality from one exposure to the next? a. Electronic timer b. Step-up transformer c. Automatic exposure control d. High frequency generator
C. The AEC is calibrated to provide the images most preferred by the radiologists.
Which of the following is surrounded by a negatively charged focusing cup? a. Step-down transformer b. Rectifier c. Filament d. Timer
C. The filament and focusing cup are part of the cathode assembly. The focusing cup has a negative charge at the moment of exposure so as to repel the electrons from the cathode.
In digital fluoroscopy, the image must be turned into digital form by what device? a. Digital-to-analog converter b. Flux capacitor c. Analog-to-digital converter d. DVD-ROM
C. The information acquired by scanning the imaging plate must be converted from its analog form to digital for further manipulation. This is an extra step when compared with direct digital radiography (DR).
Which of the following is located between the patient and the image receptor? a. Anode b. mA meter c. Ionization chamber d. Falling load generator
C. The ionization chamber is a wafer-thin chamber containing gas that is ionized by the x-rays passing through it. At a predetermined level of ionization, current flows that terminates the exposure.
What is the most commonly used AEC? a. Anode b. mA meter c. Ionization chamber d. Falling load generator
C. The ionization chamber is located between the patient and the image receptor. Phototimers are seldom used.
What is the transformer used to boost voltage to kilovoltage levels called? a. Autotransformer b. Step-down transformer c. Step-up transformer d. Low-voltage transformer
C. The voltage is varied at the autotransformer, then boosted to kilovoltage levels by the step-up transformer.
Where does thermionic emission occur? a. Step-down transformer b. Rectifier c. Cathode d. Timer
C. Thermionic emission is the boiling off of electrons from the filament wire.
The input phosphor of the image-intensifier tube converts: a. Electron energy to x-ray energy b. X-rays and heat to visible light c. X-ray energy to visible light d. X-ray energy to an electronic image
C. This is the point where the rays exiting the patient strike the input phosphor and it glows with visible light, releasing electrons from the photocathode.
Programs that deal with the safe and reliable operation of equipment and programs that address all aspects of the delivery of radiology services are called: a. Quality assurance and quality control b. Total quality improvement c. Quality control and quality assurance d. Total quality management
C. This question asks for two answers; be sure you know what is meant by each term.
The primary advantage of three-phase power is that: a. Voltage drops to zero only 6 times per second b. Voltage drops to zero only 12 times per second c. Voltage never drops to zero d. Voltage is always at peak value
C. Three-phase power produces higher average photon energy than single-phase power.
Most of the energy conversion in the x-ray tube produces: a. X-rays b. Light c. Heat d. Current
C. X-rays and heat are produced at the anode. This is the result of a massive energy conversion in which more than 99% of the incident electrons' kinetic energy is converted to heat energy, while less than 1% is converted to x-ray energy. This is a clear example of the law of conservation of energy. No light is produced in the x-ray tube.
The primary type of grid used in diagnostic imaging is: a. Crosshatch b. Parallel c. Rhombic d. Focused
D.
Single-phase, full-wave rectification produces: a. Direct current b. Pulsating direct current c. Pulsating direct current with 120 pulses per second d. Pulsating direct current with 120 pulses per second and 100% ripple
D. Although A, B, and C are all good answers, remember that we need to choose the one best answer, which is D. You are not likely to encounter this type of wording, but this question is a good exercise to remind you to look for the one best answer.
Exposure linearity must be accurate to within: a. 4 b. 5% c. 2% of SID d. 10%
D. Be sure to review these quality control standards before you take the certification exam.
The test that measures the accuracy of adjacent mA stations is: a. Exposure reproducibility b. Spinning top test c. Pinhole camera d. Exposure linearity
D. Be sure to review these quality control standards before you take the certification exam.
Effective focal-spot size may be measured using the following tool(s): a. Slit camera b. Star test pattern c. Pinhole camera d. All of the above
D. Be sure to review these quality control standards before you take the certification exam. Though 'all of the above' is not used on the ARRT exam review questions like this can assess if you really know the various equipment used.
The x-ray beam is: a. Heterogeneous—all rays possess the same energy b. Homogeneous—all rays possess the same energy c. Monoenergetic—all energies correspond to the kVp d. Heterogeneous or polyenergetic—consisting of many different energies (wavelengths)
D. Choice A is correct in stating that the x-ray beam is heterogeneous, but the second half of choice A is incorrect
What device always delivers the shortest exposure time possible? a. Anode b. mA meter c. Ionization chamber d. Falling load generator
D. Coupled with an electronic timer, this results times as short as 1/1000 second.
Electromagnetic induction is the process of causing an electrical current to flow in a conductor: a. When it is placed in contact with another conductor b. When it is placed in contact with an insulator c. When it is placed in contact with a superconductor d. When it is placed in the magnetic field of another conductor
D. Electromagnetic induction does not require that two conductors touch each other.
Calculating heat units for three-phase, 12-pulse equipment requires the use of ____ as a constant; calculating heat units for single-phase equipment requires the use of ____ as a constant; calculating heat units for three-phase, 6-pulse equipment requires the use of ____ as a constant. a. 1, 1.35, 1.41 b. 1.35, 1, 1.41 c. Calculating heat units does not require the use of a constant because all x-rays possess the same ionizing potential d. 1.41, 1, 1.35 because average photon energy is different with each type of equipment
D. Fill-in questions may be used on the certification exam, although they probably won't have three blanks like this one. Although we don't often deal with heat units, be sure to review the constants used in heat unit production.
When a predetermined level of ionization is reached in the ionization chamber, what does the machine do? a. The unit shuts off as a result of a malfunction b. The maximum allowable time has been reached c. The highest allowable dose to the patient has been reached d. The exposure is terminated
D. Hence, the exposure time when using an AEC is very dependent upon the kVp.
Examples of dedicated x-ray equipment include: a. Mammography units b. Tomography units c. Mobile x-ray machines d. All of the above
D. Just a quick question to see if you understand dedicated equipment. "All of the above" and "None of the above" type questions are not used on the certification exam.
What regulates the duration of x-ray production? a. Step-down transformer b. Rectifier c. Cathode d. Timer
D. Most equipment uses an electronic timer.
Voltage coming to the x-ray machine is kept constant through the use of a(n): a. Autotransformer b. Step-down transformer c. Rectifier d. Line voltage compensator
D. Older x-ray machines require that the line voltage compensator be adjusted manually, whereas newer equipment lets the machine do the adjustment itself.
X-rays travel as bundles of energy called: a. Energy waves b. Phasers c. Electromagnetic bursts d. Photons
D. Photons may also be called quanta.
What type of x-ray machine uses a continually decreasing mA for the shortest times possible? a. Ionization chamber b. Portable c. C-arm d. Falling load generator
D. The falling load generator makes use of the maximum heat storage capacity at every mA and time combination. This allows for the shortest exposure time possible.
Which of the following devices is prereading? a. Step-down transformer b. Rectifier c. Timer d. kVp meter
D. The kVp meter indicates what the voltage will be after being stepped up. Hence it is prereading.
The speed of x-rays is based on: a. mAs b. kVp c. Size of the patient d. The fact that they are a form of electromagnetic radiation
D. The speed of x-ray travel is constant, regardless of the factors used to produce them.
Which device is electronic, with increments of 0.001 second? a. Step-down transformer b. Rectifier c. Cathode d. Timer
D. The timer is accurate as low as 1/1000 of a second (which is 1 ms or 0.001 second).
Which of the following statements regarding filtration is true? a. Total filtration must not be less than 2-mm aluminum equivalent b. Total filtration must remove all soft rays from the beam c. Total filtration (added + compensating) must not be less than 2.5-mm aluminum equivalent d. Total filtration (not less than 2.5-mm aluminum equivalent) =inherent filtration (glass envelope, tube housing, oil) + added filtration (aluminum)
D. These are detailed statements attempting to define the amount of filtration required. D is the most complete and accurate of all the choices. A is incorrect as to amount, B is incorrect because we cannot remove all soft rays from the beam, and C is incorrect because compensating filtration is added only for certain examinations.
The process of thermionic emission causes: a. Electrons to boil off the anode b. The anode to spin c. The cathode to cool quickly d. Electrons to boil off the filament
D. This causes a space charge or electron cloud to form around the filament.
What device increases voltage approximately 500 times? a. Anode b. mA meter c. Ionization chamber d. Step-up transformer
D. This is where voltage is boosted to kilovoltage levels.
The increase in average photon energy when using three-phase, 6-pulse equipment compared with single-phase equipment is: a. 1.35% b. 41% c. 1.41% d. 35%
D. This is why the formula for heat units for three-phase, six-pulse equipment is multiplied by 1.35.
What device uses maximum heat storage ability of the tube to deliver mAs? a. Anode b. mA meter c. Ionization chamber d. Falling load generator
D. This type of generator allows extremely short exposure times.
Wavelength is defined as the distance from: a. The x-ray tube to the patient b. The cathode to the anode c. The bottom of a wave to the top d. Peak to peak of the wave
D. Wavelength can be measured from crest to crest or trough to trough.
Electromagnetic radiation travels in bundles of energy called: a. Protons b. Phasers c. Electrons d. Photons
D. X-rays exit the x-ray tube in bursts of energy called photons.
When a quality control test is performed to ensure that the penetrating ability of the x-ray beam is accurate, the result must be within what amount of the control panel setting? a. 2% of SID b. 4% c. 10% d. 4
D. kVp must be within plus or minus 4 of what is set.
