Exam 2

Question 1

What is the definition of radiation in dental radiography?

Answer 1

A form of energy carried by waves or a stream of particles.

Question 2

Who discovered the X-ray?

Answer 2

Willhelm Conrad Roentgen, on November 8, 1895.

Question 3

What is the main function of a radiograph?

Answer 3

To produce a two-dimensional image of a three-dimensional object using ionizing radiation.

Question 4

What is the role of a dental radiographer?

Answer 4

To position, expose, and process dental x-ray image receptors.

Question 5

What is an image receptor in dental radiography?

Answer 5

A recording medium such as x-ray film, phosphor plate, or digital sensor.

Question 6

Who is credited with the first practical use of radiographs in dentistry?

Answer 6

C. Edmund Kells.

Question 7

What particle has a positive charge within an atom?

Answer 7

Proton.

Question 8

Which force maintains electrons in their orbits around the nucleus?

Answer 8

Electrostatic force.

Question 9

Define ionization in atomic structure.

Answer 9

The process by which ions are formed by the gain or loss of an electron.

Question 10

What is primary radiation?

Answer 10

The penetrating x-ray beam produced at the anode target in the tubehead.

Question 11

What is the function of the lead collimator in an x-ray tubehead?

Answer 11

To restrict the size of the x-ray beam.

Question 12

What process occurs when tungsten filaments are heated, releasing electrons?

Answer 12

Thermionic emission.

Question 13

Which radiation effect involves a dose threshold and increases in severity with dose?

Answer 13

Nonstochastic (deterministic) effects.

Question 14

What describes a linear, nonthreshold dose-response curve?

Answer 14

Tissue response is directly proportional to the dose, with no threshold for damage.

Question 15

Which cells are the most radiosensitive?

Answer 15

Small lymphocytes.

Question 16

How is “absorbed dose” measured in traditional units?

Answer 16

Rad (radiation absorbed dose).

Question 17

What SI unit is equivalent to the rem for dose equivalent?

Answer 17

Sievert (Sv).

Question 18

What is the ALARA principle in radiation safety?

Answer 18

Keep radiation exposure as low as reasonably achievable.

Question 19

Who is credited with creating the first dental radiograph and in what year?

Answer 19

Otto Walkhoff, in 1895.

Question 20

What is Bremsstrahlung, or “braking radiation”?

Answer 20

Electromagnetic radiation produced when charged particles are slowed or deflected by atomic nuclei.

Question 21

What is the maximum permissible dose (MPD) for occupationally exposed dental radiographers per year?

Answer 21

50 mSv/year (0.05 Sv/year or 5.0 rem/year).

Question 22

What part of the tubehead absorbs heat created during x-ray production?

Answer 22

Insulating oil.

Question 23

What is the purpose of the thyroid collar in patient protection?

Answer 23

To protect the thyroid gland from scatter radiation.

Question 24

Which cells are classified as radioresistant?

Answer 24

Nerve cells and mature bone cells.

Question 25

What term describes the elapsed time between radiation exposure and the appearance of clinical signs?

Answer 25

Latent period.

Question 26

What is Acute Radiation Syndrome (ARS)?

Answer 26

A short-term effect of radiation exposure that causes nausea, vomiting, diarrhea, and hair loss.

Question 27

What unit is used to measure ionization in air for x-rays?

Answer 27

Roentgen (R).

Question 28

Who developed the first hot-cathode x-ray tube?

Answer 28

William D. Coolidge in 1913.

Question 29

What is inherent filtration in x-ray equipment?

Answer 29

The aluminum disc covering in the x-ray tube that filters out non-useful, longer-wavelength x-rays.

Question 30

What theory explains radiation injury from the formation of toxins within a cell?

Answer 30

Indirect theory.

Question 31

Which type of radiation interaction creates an image by passing through the patient without interaction?

Answer 31

No interaction.

Question 32

What is the function of a collimator in dental radiography equipment?

Answer 32

To restrict the size and shape of the x-ray beam, reducing patient exposure.

Question 33

What federal act standardizes x-ray equipment performance?

Answer 33

The Radiation Control for Health and Safety Act of 1968.

Question 34

What is the role of a film badge for personnel monitoring?

Answer 34

To measure radiation exposure over time, usually worn for a month and sent for analysis.

Question 35

What is the difference in exposure between an 8-inch and a 16-inch PID?

Answer 35

The 16-inch PID reduces exposure by creating a more focused beam.

Question 36

What technique did C. Edmund Kells invent, and how did it contribute to dental radiography?

Answer 36

William H. Rollins, for developing the first dental x-ray unit and advocating for radiation safety.