Question 1

The component of the x-ray machine that functions in positioning the tubehead is the:

Accepted Answer

The extension arm functions in positioning the tubehead.
The kilovoltage selector is used to control the penetrating power of the x-ray beam.
The control panel contains the master switch,an indicator light,selector buttons,and an exposure button.
The cathode supplies the electrons necessary to generate x-rays.

Question 2

In dentistry,the _____ the wavelengths of the x-rays,the greater their energy and their usefulness.

Accepted Answer

The shorter the wavelength of the x-rays,the greater their energy and usefulness in dentistry.
Longer wavelengths are weaker and have less energy.
The ionized electrons produce x-rays.
Wavelengths can be shorter or longer,but they all have the same wavelike shape.

Question 3

One of the rules of radiation protection is never stand closer than _____ feet from the x-ray unit during an exposure unless you are behind a barrier.

Accepted Answer

One of the rules of radiation protection is never stand closer than 6 feet from the x-ray unit during an exposure unless you are behind a barrier.

Question 4

Which of the following statements is true concerning the structure of the atom?

Accepted Answer

The orbital path of an electron around the nucleus is called an electron shell.Each shell can contain only a specific number of electrons.The electrons are maintained in their orbits by electron binding energy,a force similar to gravity.
The nucleus contains protons and neutrons.
Electrons have very little mass.Photons have no mass.
Electrons remain stable in their orbit around the nucleus until x-ray photons collide with them.

Question 5

A lead apron and a thyroid collar:

Accepted Answer

A lead apron and a thyroid collar must be used on all patients for all exposures.
This rule applies to all patients regardless of age,gender,or the number of films being exposed.

Question 6

Which of the following tissues has the highest radiation sensitivity?

Accepted Answer

Small lymphocytes,bone marrow,and reproductive cells have the highest radiation sensitivity.
Salivary gland,thyroid gland,kidney,muscle,and nerve tissues have relatively low radiation sensitivity.

Question 7

The dentist who is credited with the first practical use of radiographs in dentistry in 1896 is:

Accepted Answer

Dr.C.Edmund Kells is the New Orleans dentist credited with the first practical use of radiographs in dentistry.
Roentgen discovered the x-ray in 1895.
G.V.Black standardized many materials and instruments and originated the cavity preparation using "extension for prevention."
John Greenwood was a dentist to George Washington.

Question 8

The uses of dental images include the detection of:

Accepted Answer

The uses of dental images include the detection of bone loss in its early stages.
Incipient occlusal lesions are not usually visible on dental images and are detected with a dental explorer.
Periodontal probing depths cannot be determined by dental images and are detected with a periodontal probe.
Percussion sensitivity is not determined by dental images.It is usually detected with the end of the handle of a dental mirror.

Question 9

Damage caused by ionizing x-radiation to genetic cells:

Accepted Answer

X-rays can affect both genetic and somatic cells.Damage to genetic cells is passed on to succeeding generations.
Damage to cells of somatic tissue affect only the person being exposed.
Damage to genetic cells can affect any member of the dental team and the patient.
The cells of the eye,skin,and oral mucosa are not genetic,but somatic,cells.

Question 10

The sharpness of a radiographic image can be improved by:

Accepted Answer

Smaller film crystal size will improve the sharpness of a radiographic image.
A smaller focal spot size will improve the sharpness of a radiographic image.
Fast film speeds result in less sharp detail because of the large crystal size.
Any movement of the patient will degrade the sharpness of the image.

Question 11

The term _____ is used to describe areas that appear dark on the image; _____ is the term used to describe areas that appear white or light gray.

Accepted Answer

Areas on the image that appear dark are radiolucent; areas that appear white or gray are radiopaque.

Question 12

Exposure to radiation:

Accepted Answer

Exposure to radiation,no matter how small,has the potential to cause harmful biologic changes.
There is no safe dose of radiation; benefits must be titrated against risks.
Because the body has some reparative capacity,it is thought that a series of smaller doses is safer than a single,large dose.
Although it is true that radiation from an x-ray machine does not involve particulate radiation,exposure may still be harmful.

Question 13

All of the following structures will appear radiolucent on dental x-ray film except:

Accepted Answer

Metal restorations will appear radiopaque on dental x-ray film.Soft tissue,air spaces,abscesses,tooth decay,and the dental pulp will appear radiolucent.

Question 14

The range of shades of gray between black and white on an image is called:

Accepted Answer

The image appears in a range of shades from black to white with multiple shades of gray.The range of shades of gray is called contrast.
Density refers to the overall blackness or darkness of an image.
Sharpness refers to how well the image reproduces details of an object.
Focus point is not a term used in dental imaging.

Question 15

Secondary radiation:

Accepted Answer

Secondary radiation refers to x-radiation that is created when the primary beam interacts with matter.Primary radiation is often referred to as the useful beam or primary beam.

Question 16

The heart of the x-ray generating system is the:

Accepted Answer

The x-ray tube is the heart of the x-ray generating system and contains the elements that produce the x-rays.
Insulating oil surrounds the tube and absorbs the heat produced in the tube.
A transformer serves to regulate the voltage for the tube.
The PID is attached to the metal housing of the tubehead and directs the primary beam.

Question 17

The Guidelines for Prescribing Dental Radiographs issued by the American Dental Association and the FDA recommend which of the following dental imaging procedures for a pregnant patient?

Accepted Answer

With the use of the lead apron during radiographic imaging procedures,the amount of radiation received in the pelvic region is nearly zero; thus,dental radiographic imaging procedures do not need to be altered because of pregnancy.
Dental x-rays have been shown to be safe when using proper protection.

Question 18

Anything that occupies space and has a form or shape is:

Accepted Answer

Anything that occupies space and has a form or shape is matter; matter is composed of atoms and molecules.
Energy is defined as the ability to do work.
A solid is a form of matter.
A photon is a tiny bundle of pure energy that has no weight or mass.

Question 19

The degree of density or blackness on an image is controlled by the:

Accepted Answer

The degree of density or blackness of an image is controlled by the milliampere seconds.
The low-voltage circuit lights the indicator light on the panel.
The kilovoltage controls the contrast.
The PID serves to direct the path of the x-ray beam.

Question 20

The x-ray was discovered on November 8,1895,by:

Accepted Answer

Wilhelm Conrad Roentgen discovered the x-ray on November 8,1895.This discovery revolutionized diagnostic capabilities and changed the practice of medicine and dentistry forever.
John Greenwood was a dentist in New York City in 1785.
G.V.Black was an American dentist who taught at Northwestern University.
Edmund Kells was a dentist in New Orleans who advanced the use of intraoral dental radiography.

Quiz 38: Foundations of Radiography, Radiographic Equipment, and Radiation Safety