Principles of Image Production 1-8

If an atom has 15 electrons, which will be the outermost shell? a. "O" b. "L" c. "N" d. "M"

"M"-With 15 electrons, 2 will fill the K shell, 8 will fill the L shell, and 5 will fill the M shell.

The cathode includes the Selected Answer: a. envelope b. filaments c. focusing cup d. A and B e. B and C

B and C-The cathode includes both the filaments and the focusing cup.

The device that is located just under the x-ray table and holds the image receptor in place is the

Bucky assembly-The Bucky assembly holds the image receptor in place and also includes a grid

Image intensification is part of a. a film-screen imaging system b. a digital imaging system c. a fluoroscopic imaging system d. all of the above

C fluoroscopic imaging system-Image intensification applies only to fluoroscopy.

Excessive heat may be transferred to the rotor bearings, resulting in a. the anode rotating faster than it should b. the anode rotating slower than it should c. the anode rotating unevenly d. all of the above

C the anode rotating unevenly-When the rotor bearings heat up they may prevent the anode from rotating evenly

The electron shell closest to the nucleus is lettered. "E" "K" "H" "M" "E"

The innermost electron shell is the "K" shell.

A continuous emission spectrum is a graphic representation of

bremsstrahlung radiation

Place the following film-screen imaging steps in the correct order, from beginning to end: I remnant radiation is absorbed by intensifying screensII chemical processing creates a permanent imageIII light from intensifying screens expose film emulsionIV remnant radiation reaches the cassette

c. IV, I, III, II

The negative end of the x-ray tube is the

cathode

A discrete emission spectrum is a graphic representation of

characteristic radiation-A discrete emission spectrum illustrates characteristic radiation

The device that restricts the x-ray beam to the area of interest is the

collimator-The collimator, located beneath the tube housing, restricts the x-ray beam to the area of interest

The electricity applied to the tube during x-ray production is controlled at the

control panel-Setting the kilovoltage and milliamperage appropriate for the radiographic examination is done at the control panel.

Imaging tissues with lower atomic numbers results in

decreased attenuation

When an atom becomes negatively or positively charged it is usually due to a change in the number of

electrons-In that there is a weaker bond, the addition or loss of electrons typically produces a charged atom.

The tube rating chart plots mA, kVp, and

exposure time

The step-down transformer is found on the

filament circuit

The filaments within the x-ray tube are found on the

filament circuit-The filaments inside the x-ray tube are found on the filament circuit.

Chemical processing is used to create the manifest image in

film-screen imaging

A device that converts mechanical energy to electrical energy is a

generator- converts mechanical energy, such as wind or moving water, to electrical energy

The primary advantage of a rotating anode is that it allows

greater heat capacity at the anode-By having a focal track, the rotating anode allows greater heat capacity at the anode, allowing larger x-ray exposures.

A higher energy beam is said to be a ______ beam.

hard

Thermionic emission is

heating the filament until electrons are boiled off

Pitting of the anode is the result of

high exposures-Consistently using very high exposures may result in pitting of the anode

The primary purpose of the step-down transformer is to

increase the amperage going to the filaments-Although the step-down transformer does reduce the voltage, its primary purpose is to increase the amperage to the filaments, allowing the thermionic emissions of electrons

A low-kilovoltage x-ray beam results in

increased attenuation-A low kVp produces a low-energy beam that is more likely to be absorbed or scattered, increasing attenuation.

The process of removing an electron from an atom is

ionization-Removal of an electron from an atom creates an ion and the process is called ionization

A transformer with 100 times more turns on the secondary side as compared with the primary

is a step-up transformer-A transformer with 100 times more turns on the secondary wire is a step-up transformer, resulting in 100 times the voltage

When a switch is turned on, the electric circuit

is closed-Turning a switch on closes the circuit, allowing the flow of electrons

The purpose of the focusing cup is to

keep the electrons together-The purpose of the focusing cup is to keep the electrons from spreading apart.

The focusing cup is able to keep the electrons together because

like charges repel-The focusing cup is able to keep the electrons together because the negative charge of the focusing cup repels the negative charges of the electrons, pushing them together

The device that adjusts the incoming power supplied to the x-ray circuit to maintain 220 V is the

line compensator-The line compensator adjusts the incoming voltage to maintain a constant 220 V

Which of the following is the primary factor controlling quantity?

mAs- are the primary controlling factor for beam quantity

A device that converts electrical energy to mechanical energy is a

motor-The motor converts electrical energy to mechanical energy

The purpose of grounding is to

neutralize a charged object-Grounding is a protective measure that neutralizes charged objects.

The y-axis for all emission spectra represents the

number of photons-The y-axis provides information regarding the number of photons.

Complete absorption of the diagnostic range x-ray photon is the interaction known as

photoelectric interaction-The photoelectric interaction results in complete absorption of the x-ray photon.

Differential absorption occurs because different tissues have varying amounts of

photoelectric interactions

The beam that is found leaving the collimator and exposes the patient is called the

primary beam

The autotransformer is found on the

primary circuit-The autotransformer is found on the primary circuit.

The main power switch is found on the

primary circuit-The main power switch is found on the primary circuit

The timer circuit is found on the

primary circuit-The timer circuit is found on the primary circuit.

The primary side of the high-voltage transformer is found on the

primary side -of the high-voltage transformer is found on the primary circuit

The devices that change alternating to direct current are the

rectifiers

With the photoelectric interaction, after the incident photon ejects an inner-shell electron, the energy of the photon is

reduced to zero

The x-ray beam that leaves the patient to expose the IR is called the

remnant beam-The remnant beam is that portion of the primary beam that exits the patient to expose the IR

When a metallic conductor is colder:

resistance decreases

The mA meter is found on the

secondary circuit

The focusing cup is part of the

secondary circuit-The focusing cup is part of the secondary circuit

The x-ray tube (not filaments) is found on the

secondary circuit-The x-ray tube (not filaments) is found on the secondary circuit

Determining which filament will be used during an exposure is done at the operating console by the selection of

small or large focal spot-When the large or small focal spot is selected at the operating console, the associated filament will be used

The portion of the induction motor that is made of electromagnets that are energized in opposing pairs and induce an electric current with associated magnetic field is the

stator-The stator is the portion of the induction motor that is made of electromagnets that are energized in opposing pairs and induce an electric current in the rotor with associated magnetic field .

An example of an anatomic structure typically imaged with fluoroscopy is the

stomach and esophagus-The gastrointestinal system, including the stomach and esophagus, are typically imaged using fluoroscopy to see the contrast media as it moves through the system

Scattering in the diagnostic range is due to

the Compton effect-Scattering in the diagnostic range is due to the Compton effect or interaction

Assuming all other factors are accurately adjusted, the exposure time with AEC is based on

the anatomy placed over the ionization chamber-With all factors set appropriately, the length of exposure will be based on the density of the anatomy covering the detector.

L-characteristic and higher photon energies are not usually displayed on a discrete emission spectrum because

the energies of the photons produced are too low for image formation

X-rays and gamma rays differ in a. the energy source that produces them b. the effect they have on matter c. their energy level d. all of the above

the energy source that produces them-X-rays and gamma rays differ only in the energy source that produces them

Heat from x-ray production is removed through radiation by the heat traveling from

the tube to the oil bath in the protective housing

With a rotating anode, the focal spot becomes a focal a. track b. path c. circle d. stripe

track-Because the target is constantly moving during the exposure, the focal spot becomes a focal track

Three-phase power a. uses three AC waveforms at the same time b. results in three times the ripple c. is half-wave rectified d. A and B

uses three AC waveforms at the same time-Three-phase power uses three AC waveforms that are 120 degrees out of phase with each other.

Except for the K shell, the maximum number of electrons that can be in the outermost shell of an atom is a. 4 b. 8 c. 32 d. 16

8-With the exception of the K shell, no more than 8 electrons can be in the atom's outermost shell. This is called the octet rule.

Which of the following is an example of an image receptor? a. Film-screen. b. Digital. c. Absorption. d. A and B.

A and B.-Film-screen and digital are types of image receptors

Compton scattering typically occurs with x-ray photons in the energy range of

20-40 keV-Most x-ray photons that produce Compton interactions range from 20 to 40 keV

How many heat units are produced with an exposure using a single phase x-ray unit, 75 kVp, and 50 mAs? a. 5,063 HU. b. 5,288 HU. c. 5,438 HU. d. 3,750 HU.

3,750 -Because mAs is the product of mA and time, the heat units for this single-phase unit (correction factor of 1) is 1 ´ 75 ´ 50, or 3,750 HU.

The N shell can hold _______ electrons. a. 64 b. 32 c. 4 d. 8

32-Based on the formula 2n2, the N (fourth) shell can hold 2 ´ 42 electrons, or 32.

How much current is needed to heat the filament enough to produce a 100-1000 mA tube current?

5 A to 7 A-5-7 A of current must pass through the filament to produce a tube current from 100 mA to 1000 mA

If the intensity of the beam is 900 mR at a distance of 21 inches, what does the distance need to be for the intensity to measure 100 mR?

63 inches.

A filament electron removes a K shell electron and an M shell electron fills the vacancy. The K shell binding energy is 69.5 keV and the M shell binding energy is 2.8 keV. What is the energy of the K-characteristic photon produced?

66.7 keV-The energy of the photon produced is determined by subtracting the binding energy of the outer shell electron from the binding energy of the inner shell electron (69.5 - 2.8 = 66.7).

Most x-ray tube target angles range between

7 and 18 degrees-Most x-ray tubes have a target angle between 7 and 18 degrees.

If the distance from the source is changed from 72 inches to 36 inches and the original beam intensity was 200 mR, what is the new intensity?

800 mR-Based on the inverse square law, halving the distance from the source results in four times the intensity. I1/I2 = d22/d21 ; 200/I2 = 362/722 ; 1296 I2 = 1036800 ; I2 = 800 mR

At the anode target, ___ of the energy from filament electrons is lost as heat and ___ will result in x-ray production.

99%; 1%

Which of the following factors affect beam quantity? a. kVp. b. Distance. c. Filtration. d. All of the above.

All of the above.

Current that changes direction in the conductor is

Alternating current- is constantly changing direction in the conductor

The line compensator is typically wired to the

Autotransformer

The major source of radiation exposure to technologists is due to

Compton interactions-Compton scattering is the major source of occupational exposure.

Which of the following occurs first during x-ray production? a. Kilovoltage is applied to anode and cathode. b. Voltage is transformed to kilovoltage. c. Thermionic emission. d. Current passes through the rheostat.

Current passes through the rheostat.

As a wave's wavelength increases, its frequency

Decreases

Which of the following devices allow the electricity to flow in one direction only?

Diode.-The diode, or solid-state rectifier, allows electrons to flow in one direction only

Place the following events leading to the production of x-rays in order, from first to last I. resistance is adjusted at the rheostatII. filament is heatedIII. filament current is increasedIV. electrons are boiled off filament

I, III, II, IV

Place the following digital imaging steps in the correct order, from beginning to end: I remnant radiation reaches the digital image receptorII the manifest image is displayed on a monitorIII the manifest image can be adjusted because it is composed of digital dataIV the latent image is processed by the computer

I, IV, II, III

Place the following events leading to the production of x-rays in order, from first to last I. electrons are boiled off filamentII. electricity leaves the autotransformerIII. electricity goes to primary side of step-down transformerIV. filament is heated

II, III, IV, I

Place the following events leading to the production of x-rays in order, from first to last I. kilovoltage is rectifiedII. voltage is adjusted at the autotransformerIII. anode and cathode develop large positive and negative charges IV. voltage changes to kilovoltage

II, IV, I, III

Place the following events leading to the production of x-rays in order, from first to last I. alternating current is converted to direct currentII. voltage is adjusted at the autotransformerIII. kilovoltage leaves the step-up transformerIV. voltage goes to primary side of step-up transformer

II, IV, III, I

The ability to remove electrons from an atom is

Ionization-Ionization is the ability to remove electrons from an atom.

Dense material, like bone, is considered:

Radiopaque-Bone is radiopaque because it readily absorbs radiation and prevents it from reaching the image receptor

An adjustable form of a resistor is the

Rheostat-The rheostat is a resistor that can be adjusted

The cloud of electrons produced through thermionic emission is more accurately called a(n)

Space charge is the more accurate name for the cloud of electrons.

A general purpose radiographic tube typically has ____ filament(s).

Two-A typical tube has two filaments; it is sometimes referred to as a dual-focus tube

Which of the following occurs first during x-ray production? a. Voltage level is adjusted at autotransformer. b. Alternating current is changed to direct current. c. Voltage is transformed to kilovoltage. d. Kilovoltage is applied to anode and cathode.

Voltage level is adjusted at autotransformer.-Prior to the alternating electrical voltage being transformed to kilovoltage and changed to direct current, the correct voltage level must be adjusted at the autotransformer

Placing filtration in the path of the beam results in

a harder beam-Adding filtration removes lower energy photons, resulting in a higher energy, or harder beam.

Radiation interacting with bone is more likely to be absorbed, resulting in that area of the image being

a light shade of gray-Because few photons are transmitted through the bone, the result is that this area of the image is lighter than the rest.

Filtration placed in the path of the x-ray beam

absorbs low-energy photons-Beam filtration reduces beam quantity by absorbing low-energy photons.

The anode serves as a(n) a. target for the electron interaction to produce x-ray b. electrical conductor c. heat conductor d. all of the above

all of the above

The energy of the brems photon depends on a. the original energy of the filament electron b. the strength of the attraction between the electron and the nucleus c. the energy of the filament electron as it leaves the tungsten atom d. all of the above

all of the above

The energy of the characteristic x-ray photon depends on a. the binding energy of the inner-shell electron b. the energy level of the filament electron c. the shell of the electron that is dropping into the vacancy d. all of the above

all of the above

The protective tube housing helps to a. keep the tube cool b. prevent electrical shocks to the radiographer c. limit leakage radiation d. provide solid, stable mechanical support e. all of the above

all of the above

The various shades of gray or brightness created on the radiographic image a. are present because of differential absorption b. makes the anatomic structures visible c. represent the radiation that was absorbed or transmitted d. all of the above

all of the above

The discrete emission spectrum typically displays a. K-characteristic photon energies b. L-characteristic photon energies c. all of the above d. none of the above

all of the above-The discrete emission spectrum typically displays K- and L-characteristic photon energies

The positive end of the x-ray tube is the

anode- is the positive end of the x-ray tube

The only adjustable transformer in the x-ray circuit is the

autotransformer

The device referred to as the kVp selector is the

autotransformer-The autotransformer adjusts based on the kVp set at the operating console.