Evolve Review Questions

Question 1

X-rays were discovered by:

a) Heinrich Geissler
b) William Crookes
c) Wilhelm Roentgen
d) Philip Lenard

Answer 1

C) WILHELM ROENTGEN

[Roentgen discovered the x-ray in 1895. He published 3 papers detailing his methods and the properties, and characteristics of x-rays. Roentgen received the 1st Nobel Prize ever awarded in physics.]

Question 2

Which of the following was Otto Walkhoff’s contribution to dental radiography?

a) He made the 1st dental radiograph.
b) He made the 1st dental radiograph in the U.S. using a skull.
c) He exposed the 1st dental radiograph in the U.S. using a living person.
d) He developed the 1st dental x-ray unit.

Answer 2

A) HE MADE THE 1st DENTAL RADIOGRAPH.

[Walkhoff made the 1st dental radiograph. William H. Rollins developed the 1st dental x-ray unit.]

Question 3

Which of the following was the most recent development in the history of dental x-ray equipment?

a) Development of the 1st hot-cathode x-ray tube.
b) Intro of a recessed long-beam tubehead.
c) Intro of a variable kilovoltage machine.
d) Placement of a miniature version of the x-ray tube inside the head of an x-ray machine.

Answer 3

B) INTRO OF A RECESSED LONG-BEAM TUBE HEAD.

[A recessed long-beam tubehead was introduced in 1966.]

Question 4

Currently using fast film requires less than _____% of the initial exposure times used for dental radiography in 1920.

a) 2
b) 12
c) 22
d) 32

Answer 4

A) 2

[Current fast dental radiography film requires < 2% of the initial exposure time used for dental radiography in 1920, which is far superior to a 68% reduction.]

Question 5

The long-cone paralleling technique was introduced by _____ in 1947.

a) C. Edmund Kells
b) Hisatugu Numata
c) Yrjo Paatero
d) F. Gordon Fitzgerald

Answer 5

D) F. GORDON FITZGERALD

[F. Gordon Fitzgerald, the “father of modern dental radiography,” revived interest in the paralleling technique with the intro of the long-cone paralleling technique in 1947.]

Question 6

Which of the following is true concerning atomic structure?

a) Both protons and electrons carry positive electrical charges.
b) An electron does not have any mass.
c) The strongest binding energy for electrons is found closest to the nucleus.
d) The A shell is located closest to the nucleus and has the weakest binding energy.

Answer 6

C) THE STRONGEST BINDING ENERGY FOR ELECTRONS IS FOUND CLOSEST TO THE NUCLEUS.

[…whereas electrons located in the outer shells have a weak binding energy.]

Question 7

Identify the term for an atom that has lost an electron from its orbit:

a) ion.
b) photon.
c) neutron.
d) particle.

Answer 7

A) ION.

[An ion is an atom that has gained or lost an electron.]

Question 8

Identify which of the following processes occurs with ionization:

a) cell death takes place.
b) photons penetrate matter.
c) radiant energy is converted to heat.
d) an electron is displaced from its orbit.

Answer 8

D) AN ELECTRON IS DISPLACED FROM ITS ORBIT.

[Ionization occurs when an atom gains or loses an electron.]

Question 9

Identify which of the following is NOT a type of particulate radiation:

a) alpha particles.
b) beta particles.
c) protons.
d) nucleons.

Answer 9

D) NUCLEONS.

[Nucleons are not a type of particulate radiation; a nucleon is a part of an atomic nucleus.]

Question 10

Identify which of the following is NOT a type of electromagnetic radiation:

a) electrons.
b) radar waves.
c) microwaves.
d) x-rays.

Answer 10

A) ELECTRONS.

[Electrons are not a type of electromagnetic radiation.]

Question 11

Identify which of the following is NOT a property of x-ray:

a) the ability to penetrate organic matter.
b) the ability to fluoresce all materials.
c) the ability to produce ionization of matter.
d) the ability to produce a latent image.

Answer 11

B) THE ABILITY TO FLUORESCE ALL MATERIALS.

[X-rays can cause certain substances to fluoresce.]

Question 12

Identify which of the following is FALSE:

a) X-ray cause ionization.
b) X-rays cannot be focused to a point.
c) X-rays have no charge.
d) X-rays travel at the speed of sound.

Answer 12

D) X-RAYS TRAVEL AT THE SPEED OF SOUND.

Question 13

Identify which of the following elements is/are located within the x-ray tube:

a) anode.
b) cathode.
c) focusing cup.
d) all of the above.

Answer 13

D) ALL OF THE ABOVE.

[The anode and cathode are the electrodes inside the x-ray tube, and the focusing cup is a part of the cathode.]

Question 14

Identify the part of the x-ray tube that contains the focal spot:

a) anode
b) cathode
c) filament
d) focusing cup

Answer 14

A) ANODE

[The cathode does not that contain the focal spot but does contain the tungsten filament and focusing cup. The filament is a part of the cathode electrode and does not contain the focal spot. The focusing cup is a part of the cathode electrode and does not contain the focal spot.]

Question 15

Identify the part of the x-ray tube where x-ray photons are produced:

a) at the positively charged anode.
b) at the positively charged cathode.
c) at the negatively charged anode.
d) at the negatively charged cathode.

Answer 15

A) AT THE POSITIVELY CHARGED ANODE.

[The cathode supplies electron to generate x-rays; x-rays are not produced at this electrode.]

Question 16

Which of the following is true of the conversion of the kinetic energy of the electrons into x-ray photons through general radiation?

a) Most x-rays are produced in this manner; approximately 99% of the x-ray energy produced at the anode can be classified as general radiation.
b) General radiation consists of x-rays of many different energies and wavelengths.
c) General radiation is produced when an high-speed electron dislodges an inner-shelf electron from the tungsten atom.
d) General radiation occurs only at 70 kVp and above.

Answer 16

B) GENERAL RADIATION CONSISTS OF X-RAYS OF MANY DIFFERENT ENERGIES AND WAVELENGTHS.

[Most electrons just miss the nucleus of the tungsten atom. The electron that misses the nucleus continues to penetrate many atoms, producing lower-energy x-rays before it imparts all of its kinetic energy. As a result, general radiation consists of x-rays on many different energies and wavelengths.]

Question 17

Identify the best description of primary radiation:

a) the beam that exits the tubehead.
b) the beam that is created when x-rays contact matter.
c) the beam that is deflected from its path by matter.
d) the beam that is less penetrating.

Answer 17

A) THE BEAM THAT EXITS THE TUBEHEAD.

Question 18

Identify the term used to describe the x-ray beam that exits the position-indicating device (PID):

a) primary radiation.
b) secondary radiation.
c) scatter radiation.
d) direct radiation.

Answer 18

A) PRIMARY RADIATION

[The beam created when x-rays contact matter is termed secondary radiation. The beam that is deflected from its path by interaction with matter is termed scatter radiation. Direct radiation is not a term used in dental radiography.]

Question 19

Identify the radiation produced when matter is irradiated by x-rays:

a) leakage radiation.
b) primary radiation.
c) diverging radiation.
d) secondary radiation.

Answer 19

D) SECONDARY RADIATION

[Secondary radiation is produced when matter is irradiated by x-rays. Leakage radiation is any radiation, except for the primary beam, that is emitted from the dental tube head. Primary radiation is the beam that exits the tubehead. Diverging radiation is another term to describe radiation that is scattered.]

Question 20

Identify the characteristics of x-rays produced with a high kilovoltage:

1. more penetrating
2. less penetrating
3. of longer wavelength
4. of shorter wavelength

a) 1 & 3
b) 1 & 4
c) 2 & 3
d) 2 & 4

Answer 20

B) 1 & 4

[When kilovoltage peak settings are increased, a higher-energy x-ray beam is produced with a more penetrating beam; more penetrating x-rays with greater energy also demonstrate shorter wavelengths.]

Question 21

Identify the function of the kilovoltage setting on the x-ray machine:

a) controls the quantity of x-rays produced.
b) controls the penetrating power of the x-ray beam.
c) controls the number of photons available.
d) all of the above.

Answer 21

B) CONTROLS THE PENETRATING POWER OF THE X-RAY BEAM.

Question 22

Which of the following terms is used to describe the overall blackness or darkness of an image?

a) Contrast
b) Density
c) Overexposure
d) Intensity

Answer 22

B) DENSITY

Question 23

Which of the following exposure factors is used to modify contrast in dental radiography?

a) Milliamperage
b) Kilovoltage
c) Exposure time
d) Processing time

Answer 23

B) KILOVOLTAGE

[An increase in milliamperage increases the overall density of the image and results in a darker image. This increase would effectively decrease contrast but also would reduce the quality of the image. Increasing the exposure time without modifying the kilovoltage peak or milliamperage will result in an image with increased density, reduced contrast, and decreased image quality. Modifying processing time is not recommended as a method to modify contrast in dental radiography.]

Question 24

Which of the following choices correctly identifies the density and contrast of a film produced using a high kilovoltage setting?

a) Increased density; low contrast
b) Increased density; high contrast
c) Decreased density; low contrast
d) Decreased density; high contrast

Answer 24

A) INCREASED DENSITY; LOW CONTRAST

[A high kilovoltage setting will produce a darker image of increased density, but it will produce an image with “low” rather than “high” contrast and many shades of gray instead of black and white.]

Question 25

Identify the kilovoltage peak (kVp) setting that produces the greatest contrast among images on a radiograph:

a) 65 kVp.
b) 75 kVp.
c) 80 kVp.
d) 90 kVp.

Answer 25

A) 65 kVp

[Greatest contrast refers to an image that has high contrast, or many black and white areas; this type of image is produced with lower kilovoltage peak settings (65-70 kVp).]

Question 26

Identify the unit of time used to measure x-ray exposure:

a) ampere.
b) milliampere.
c) volt.
d) impulse.

Answer 26

D) IMPULSE.

[Exposure time is measured in impulses because x-rays are created in a series of bursts or pulses rather than a continuous stream.]

Question 27

Identify the function(s) of the milliamperage setting on the x-ray machine:

a) controls the quantity of x-rays produced.
b) controls the temperature of the tungsten filament.
c) controls the quality of the x-rays produced.
d) a and b.

Answer 27

D) A AND B.

[Milliamperage does not control the quality of the x-rays produced. The quality of x-rays produced is controlled by the kilovoltage.]

Question 28

Identify which of the following is determined by the milliamperage and exposure time settings:

a) energy of the radiation produced.
b) amount of film fog.
c) quantity of x-rays produced.
d) penetrating ability of the x-ray beam.

Answer 28

C) QUANTITY OF X-RAYS PRODUCED.

[Both milliamperage and exposure time settings determine the quantity of x-rays produced.]

Question 29

Identify which of the following results when a film is exposed with a high milliamperage setting:

a) high contrast.
b) low contrast.
c) increased density.
d) decreased density.

Answer 29

C) INCREASED DENSITY.

[A high milliamperage setting produces an image of increased overall density, or a darker image, rather than an image of decreased density.]

Question 30

Identify the intensity of the x-ray beam if the selected position-indicating device (PID) is increased from 8 in. to 16 in.:

a) the beam will be one-quarter as intense.
b) the beam will be half as intense.
c) the beam will be twice as intense.
d) the beam will be four times as intense.

Answer 30

A) THE BEAM WILL BE ONE-QUARTER AS INTENSE.

[Using the inverse square law, the beam will be one-quarter as intense.]

Question 31

X-radiation causes cell damage primarily through formation of:

a) thymine dimers.
b) free radicals.
c) damage to the DNA of a cell.
d) damage to the RNA of a cell.

Answer 31

B) FREE RADICALS.

[Free radical formation occurs when an x-ray photon ionizes water, the primary component of living cells. Ionization of water results in the production of hydrogen and hydroxyl free radicals.]

Question 32

Identify the portion of the cell that is damaged when a genetic mutation results:

a) lipids.
b) proteins.
c) DNA.
d) cytoplasm.

Answer 32

C) DNA.

[DNA is a critical part of the cell and contains genetic information, which specifies the biologic development of the cell.]

Question 33

Which of the following is true of non-stochastic effects of radiation?

a) Effects occur as a direct function of the dose.
b) The severity of effects does not depend on the magnitude of the absorbed dose.
c) Effects have a threshold.
d) The probability of occurrence increases with increasing absorbed dose.

Answer 33

C) EFFECTS HAVE A THRESHOLD.

[Stochastic rather than non-stochastic effects occur as a direct function of dose. The severity of stochastic rather than non-stochastic effects does not depend on the magnitude of the absorbed dose. The probability of occurrence increases with increasing absorbed dose for stochastic rather than non-stochastic effects of radiation.]

Question 34

Identify which of the following is TRUE concerning radiation injury:

a) all radiation injuries are evident immediately.
b) X-radiation only injures somatic cells.
c) Acute injury due to x-radiation exposure is common.
d) Cumulative effects of x-radiation exposure lead to health problems.

Answer 34

D) CUMULATIVE EFFECTS OF REPEATED RADIATION EXPOSURE CAN LEAD TO HEALTH PROBLEMS.

[…such as cancers, cataracts, or birth defects.]

Question 35

Which of the following types of cells are most sensitive to radiation?

1. rapidly dividing cells
2. slowly dividing cells
3. cells of children compared with cells of adults
4. cells of adults compared with cells of children

a) 1 & 3
b) 1 & 4
c) 2 & 3
d) 2 & 4

Answer 35

A) 1 & 3

[Rapidly dividing cells are more sensitive to radiation than are slowly dividing cells. Cells of children also are more sensitive to radiation than cells of adults.]