✨✨DH103 midterm study guide

Who discovered x-rays?

Roentgen

Who wrote the first dental text and introduced the bite-wing technique?

Raper

Who exposed the first dental radiograph in the U.S. (skull)?

Morton

Who used paralleling technique in practical dental radiography?

McCormack

Who exposed the first dental radiograph in the U.S. (living patient)?

Kells

Who introduced long-cone paralleling technique?

Fitzgerald

Who developed the first x-ray tube?

Coolidge

The collimator ______

restricts the size and shape of the x ray beam

is a solid piece of aluminum

is fitted within the copper stem beneath the molybdenum cup

is always round

restricts the size and shape of the x ray beam

On some dental x-ray machines, only the ____ can be altered; the other parameters are preset by the manufacturer.

kilovoltage

exposure time

PID length

milliamperage

exposure time

Which of the following are considered to be semicritical instruments?

the exposure button

receptor holding devices

the x ray control panel

the lead apron

receptor holding devices

In dental imaging, no_________ are used

critical instruments

semicritical instruments

noncritical instruments

critical instruments

A beam alignment device can be used to help the dental radiographer position the PID in relation to the _______ and the receptor

collimator

control panel

tooth

extension arm

tooth

Which of the following should you do prior to taking x rays to protect your patient from radiation exposure?

proper film processing

a thyroid collar

a lead apron

proper prescribing of radiographs

proper prescribing of radiographs

Through the use of dental images, the dental radiographer can detect ________ that cannot be detected clinically.

diseases

lesions

conditions of teeth and bones

all of the above

all of the above

In order to avoid the primary beam while taking dental images, you should stand at a ____-degree to ____-degree angle to the beam.

90; 135

An oral examination limits the practitioner to knowledge of what is seen clinically. Dental images allow the practitioner to see many conditions that are not apparent clinically.

the first statement is true; the second is false

both are false

both are true

the first statement is false; second is true

both are true

Which of the following statements is true of the receptor holder?

it requires the patient to stabilize the receptor in the mouth

it is used to align an extraoral dental x ray receptor

it is required when using the intraoral bisecting technique

it is required when using the intraoral paralleling technique

it is required when using the intraoral paralleling technique

The _____________ allow(s) for positioning of the tubehead.

extension arm

exposure button

control panel

control devices

extension arm

A _________ eliminates the need for the patient to stabilize the receptor

beam alignment device

PID

control panel

receptor holder

receptor holder

_______ regulates the manufacture and installation of dental x ray equipment

municipal government

federal government

state government

local government

federal government

You are 36 years old. What is your communicative occupational does recommended by the national Council on radiation protection and measurement (NCRP)

180 millirems

360 mSv

180 mSv

360 millirems

360 mSv

According to the recommendations (2003) of the national Council on Radiation Protection and Measurements, the current MPD for occupationally exposed persons is ______/year

5000 rem

5.0 rem

50 rem

500 millirem

5.0 rem

Which of the following types of PIDs produces scatter radiation

square

rectangular

round

conical

conical

Which type of PID would be most effective in reducing patient exposure?

an 8 inch rectangular PID

conical

a 16 inch round PID

a 16 inch rectangular PID

a 16 inch rectangular PID

A circular collimator produces a cone-shaped beam that is _______ inches in diameter

1.25

2.75

5.0

2.75

A rectangular collimator:

restricts the beam 3 times more than a circular collimator

decreases patient exposure considerably

is considerably larger than a size 2 intraoral receptor

restricts the beam less than a circular collimator

decreases patient exposure considerably

The ALARA concept states that all radiation must be kept:

as low as reasonably achievable

Critical instruments are defined as instruments:

that contact but do not penetrate bone

devices that do not come in contact with mucous membranes

that contact but do not penetrate soft tissue

that are used to penetrate soft tissue or bone

that are used to penetrate soft tissue or bone

State and federal laws require that dental x-ray machines operating above 70 kVp have a minimum total (inherent plus added filtration) of ____ mm of aluminum filtration.

1.5

2.5

5.0

2.0

2.5

Another term for infection control is ______, which means the absence of pathogens, or disease causing microorganisms

antifective

asepsis

antibiotic

antiseptic

asepsis

Pathogens are

bacteria but not viruses

viruses but not bacteria

microorganisms capable of causing disease

any microorganism

microorganisms capable of causing disease

Antiseptic is:

the absence of pathogens, or disease causing microorganisms

the use of a chemical or physical procedure to inhibit or destroy pathogens

the act of sterilizing

a substance that inhibits the growth of bacteria

a substance that inhibits the growth of bacteria

Added filtration in the dental x ray tubehead

refers to the placement of tungsten discs in the path of the x ray beam between the collimator and the tubehead seal

filters our shorter wavelength x rays from the x ray beam

results in a lower energy beam

results in a more penetrating useful beam

results in a more penetrating useful beam

Label

1 - filament and electron cloud

2 - focal spot on tungsten target

3 - glass envelope

4 - vacuum

5 - copper stem

6 - anode (+)

7 - useful x ray beam

8 - tube window

9 - cathode (-)

10 - electronic focusing cup

Label

1 - filament and electron cloud

2 - electronic focusing cup, cathode (-)

3 - x ray tube

4 - Focal spot on tungsten target

5 - copper stem, anode (+)

6 - insulating oil

7 - unleaded glass window

8 - lead collimator

9 - PID

10 - aluminum disks

11 - tubehead seal

A detector that is used to capture the dental image

sensor

pixel

direct digital imaging

digital radiography

sensor

An image receptor found in the intraoral sensor

pixel

charge-coupled device (CCD)

storage phosphor imaging

digitize

charge-coupled device (CCD)

A form of indirect digital imaging in which the image is recorded on phosphor-coated plates and then placed into an electronic processor, where a laser scans the plate and produces an image on a computer screen

storage phosphor imaging

direct digital imaging

digital radiography

sensor

storage phosphor imaging

To convert an image into digital form that, in turn, can be processed by a computer

digital subtraction

sensor

digitize

pixel

digitize

A method of obtaining a digital image in which an intraoral sensor is exposed to x-rays to capture an image that can be viewed on a computer monitor

digital radiography

direct digital imaging

charge-coupling device

pixel

direct digital imaging

a discrete unit of information; a picture element

sensor

digitize

charge-coupled device

pixel

pixel

a method of reversing the gray scale as a digital image is viewed

direct digital imaging

digital subtraction

digital radiography

sensor

digital subtraction

a filmless imaging system; a method of capturing an image using a sensor, breaking the image into electronic pieces, and presenting and storing the image using a computer

digital radiography

pixel

digital subtraction

storage phosphor imaging

digital radiography

True or False. In digital imaging, the term used to describe the picture that is produced is radiograph

false

True or False. Digital imaging requires more x-radiation than conventional radiography

false

True or False. The x-radiation source used in most digital imaging systems is a conventional dental x-ray unit

true

True or False. Compared with film emulsion, the pixels used in digital imaging are structured in an orderly arrangement

true

True or False. All intraoral sensors can be heat-sterilized after use

false

True or False. The preferred exposure method for intraoral digital imaging is the paralleling technique

true

True or False. One advantage of a digital imaging system is the superior gray-scale resolution that results

true

True or False. Digital subtraction is an advantage in digital imaging because distration background information is eliminated from the image

true

True or False. The manipulation of the origingal digital images can be considered a legal issue

true

Digital imaging was introduced to dentistry in

1968

1990

1987

1997

1987

Digital imaging can be used for:

Detecting conditions of teeth and surrounding structures

Evaluating the growth and development of jaws

Confirmation of suspected disease

All of the above

all of the above

Digital imaging requires less radiation than does conventional radiography because:

The sensor is larger

The sensor is more sensitive to x-rays

The exposure time is increased

The pixels sense transmitted light quickly

the sensor is more sensitive to xrays

The image receptor found in the intraoral sensor is termed

CCD

pixel

Semiconductor chip

Software

CCD

Digital imaging systems can be used for which images:

Bite-wing

Panoramic

Cephalometric

All of the above

all of the above

All of the following are advantages of digital imaging except:

Digital subtraction

The ability to enhance the image

Size of the intraoral sensor

Patient education

size of the intraoral sensor

Why is an increased target-receptor distance required in the paralleling technique?

to avoid image magnification

to avoid distortion

to reduce scatter radiation

to improve receptor placement

to avoid image magnification

Which describes the relationship of the central ray to the receptor in the paralleling technique?

20 degrees to the long axis of the tooth

90 degrees to the receptor and long axis of the tooth

75 degrees to the long axis of the tooth

15 degrees to the receptor and the long axis of the tooth

90 degrees to the receptor and long axis of the tooth

Which of the following about the lack of parallelism between the receptor and the long axis of the tooth is correct.

If the lack of parallelism is greater than 30 degrees, the image is generally acceptable.

If the lack of parallelism is less than 20 degrees, the image is generally acceptable.

If the lack of parallelism is less than 50 degrees, the image is generally acceptable.

If the lack of parallelism is greater than 50 degrees, the image is generally acceptable.

If the lack of parallelism is less than 20 degrees, the image is generally acceptable.

Which are advantages of the paralleling technique?

1. increased accuracy

2. simplicity of use

3. ease of duplication

4. ease of receptor placement

1, 2, 3

True or false: The advantages of the paralleling technique outweigh the disadvantages.

true

State the five rules of the paralleling technique.

Receptor placement, receptor position, vertical angulation, horizontal angulation, receptor exposure

too much vertical angulation results in images that are

elongated

foreshortened

overlapped

none of the above

foreshortened

Too little vertical angulation results in images that are

elongated

foreshortened

overlapped

none of the above

elongated

incorrect horizontal angulation results in images that are

elongated

foreshortened

overlapped

none of the above

overlapped

Which occurs can occur with the bitewing technique?

elongation

overlapped contacts

cone-cut

phalangioma

overlapped and cone-cut

Which errors can occur with the bisecting technique?

elongation

overlapped contacts

cone-cut

phalangioma

elongation

you have been using a dental x ray machine that has a 4 inch PID. your new machine has an 8 inch PID. given that all exposure factors remain the same, according to the inverse square law, the resultant beam would be _________ as intense:

one quarter

four times

half

twice

one quarter

when kilovolt is increased, a:

higher energy x ray beam with decreased penetrating ability results

higher energy x ray beam with increased penetrating ability results

lower energy x ray beam with increased penetrating ability results

lower energy x ray beam with decreased penetrating ability results

higher energy x ray beam with increased penetrating ability results

(1) Density is the overall darkness or blackness of a dental image. (2) When the kilovoltage is increased while other exposure factors remain constant, the resultant image exhibits a decreased density and appears lighter.

the first statement is true; the second is false

the first statement is false; second is true

both are true

both are false

the first statement is true; second is false

mA regulates the _______ of electrons produced at the cathode filament:

quality

power

speed

quantity

quantity

In regard to increasing density:

An increase in either kVp or mA will increase density

an increase in kV will increase density, but an increase in mA will not increase density

an increase in mA will increase density, but an increase in kV will not increase density

neither an increase in kV nor an increase in mA will increase density

an increase in either kV or mA will increase density

Aluminum filters:

remove more penetrating x rays from the beam

removie high energy x-rays from the beam

reduce the intensity of the x ray beam

decrease the mean penetrating ability of the x ray beam

reduce the intensity of the x ray beam

aluminum filters are used to remove ________ energy, _________ wavelength x rays:

high; longer

high; shorter

low; longer

low; shorter

low; longer

which of the following changes will increase x ray beam intensity:

decreasing the kilovoltage

decreasing the exposure time

decreasing the mA

decreasing the source-to-film distance

decreasing the source-to-film distance

(1) As kilovoltage, milliamperage, and time increase, x-ray beam intensity decreases. (2) As distance and filtration increase, the intensity of x-ray beam increases.

the first statement is true; second is false

the first statement is false; second is true

both are true

both are false

both are false

when contrasted with the use of 70 kV for dental x rays, the use of 60 kV produces:

less penetrating dental x rays with longer wavelength

more penetrating dental x rays with shorter wavelength

more penetrating dental x rays with longer wavelength

less penetrating dental x rays with shorter wavelength

less penetrating dental x rays with longer wavelength

interaction with the x ray photon as a result of the photoelectric effect is harmful to the patient because ionization occurs

the statement is true

the statement is false

the first part of the statement is false; second is true

the first part of the statement is true; second is false

statement is true

______ is a measurement of force that refers to the potential difference between two electrical charges:

voltage

ampere

wavelength

exposure time

voltage

which of the following statements is true of wavelength in reference to radiation?

mA controls the wavelength and energy of the x ray beam

x rays with shorter wavelength have less penetrating power

x rays with longer wavelength have less penetrating power

x rays with longer wavelength are less likely to be absorbed by matter

x rays with longer wavelength have less penetrating power

in dental radiography, the term _____ is used to describe the mean energy or penetrating ability of the x ray beam:

quantity

quality

intensity

wavelength

quality

which property of x rays allows for the image on the receptor?

effect on living tissue

penetrating power

fluorescence

focusing capability

penetrating power

which would you adjust if you wanted to produce characteristic radiation?

step-down transformer

kilovoltage

step-up transformer

mA

kilovoltage

which would you adjust if you wanted to create a larger electron cloud?

kilovoltage

mA

step-down transformer

step-up transformer

mA

the lead collimator:

restricts the size of the x ray beam

carries away the heat produced during the production of x rays

filters the longer-wavelength x rays from the beam

permits a small number of x rays to exit from the x ray tube

restricts the size of the x ray beam

which of the following statements is true of characteristic radiation?

the high speed electron passes close to the nucleus or hits the nucleus of the tungsten atom

it is the source of the majority of x rays that are produced

it only occurs at 70 kV and above

it is also known as braking radiation

it only occurs at 70 kV and above

which form of the x ray beam is most detrimental to the patient and operator?

scatter radiation

secondary radiation

useful beam

primary radiation

scatter radiation

which is the most common possibility when an x ray photon interacts with matter?

absorption or photoelectric effect

compton scatter

coherent scatter

no interaction

compton scatter

which of the following four possibilities that can occur when an x ray photon interacts with matter is responsible for producing densities on a dental receptor that make dental radiography possible?

absorption or photoelectric effect

compton scatter

coherent scatter

no interaction

no interaction

(1) X-ray photon production occurs as a result of both general and characteristic radiation. (2) General radiation accounts for a small number of x-ray photons produced because it takes high kV to dislodge the electrons from the K shell.

both statements are false

the first statement is false; second is true

the first statement is true; second is false

both are true

the first statement is true; second is false

which of the following components of the x ray machine would have two indicator lights?

x ray tubehead

extension arm

control panel

x ray tube

control panel

approximately what % of the kinetic energy of the electrons is converted to x rays at the anode?

100%

less than 1%

25%

50%

less than 1%

thermionic emission of electrons occurs at the:

tungsten filament in the cathode

copper stem

tungsten filament in the anode

molybdenum cup

tungsten filament in the cathode

in the dental x ray tube the number of electrons created is controlled by:

alternating current

direct current

kV

mA

mA

heat is a byproduct of x ray production. which component of the x ray tubehead dissipates the heat created by the production of x rays?

aluminum disks

metal housing

lead collimator

insulating oil

insulating oil

the purpose of the anode is to:

filter out nonpenetrating, longer-wavelength x rays

convert electrons into x ray photons

absorb heat created by the production of x rays

produce electrons when heated

convert electrons into x ray photons

within the x ray tube, electrons are generated by the:

tungsten filament in the anode

copper stem

tungsten filament in the cathode

molybdenum cup

tungsten filament in the cathode

which of the following statements is true of the wave concept of electromagnetic radiation?

frequency and wavelength are inversely related

velocity refers to the number of wavelengths that pass a given point in a certain amount of time

wavelength refers to the speed of the wave

frequency is defined as the distance between the crest of one wave and the crest of the next

frequency and wavelength are inversely related