Radiology Final

Front 1

In dental radiography the term _ is used to describe the mean energy or penetrating ability of the xray beam

Back 1

Quality

Front 2

Which of the following statements is/are true of wavelengths in reference to radiation?

Back 2

X-rays with longer wavelengths have less power AND X-rays with longer wavelengths are more likely to be absorbed by matter

Front 3

__ is the the measurement of force that refers to the potential difference between two electrical charges

Back 3

Voltage

Front 4

When the voltage is increased:

Back 4

Electrons move from the cathode to the anode with more speed

Front 5

Which of the following is true of the use of voltage in dental xray equipment

Back 5

Dental xray equipment requires the use of 65-100 kilovolts

Front 6

When contrasted with the use of 65 kV to 75 kV for dental X-rays the use of 85 kV to 100 kV produces

Back 6

More penetrating dental X-rays with shorter wavelengths

Front 7

The kVp represents

Back 7

Max voltage or peak of direct current

Front 8

When kilovolt peak is increased

Back 8

High energy xray beam with increased penetrating ability

Front 9

(1)Density is the overall darkness or blackness of a film. (2)When kVp is increased while other exposure factors remain constant the resultant film appears decreased density with overall lighter. Which are true?

Back 9

First statement is true second is false

Front 10

When low kilo voltage peak settings are used (65kVp-70kVp) a film with __ will result

Back 10

High contrast

Front 11

A film with low contrast (greater or equal to 90kVp)

Back 11

Useful for detection of periodontal or periapical disease and has many shades of gray

Front 12

Exposure time is measured in:

Back 12

Impulses

Front 13

Aluminum filters;

Back 13

Reduce the intensity of the xray beam

Front 14

(1)All ionizing radiations are harmful and produce biologic changes in living tissue. (2) the amount of radiation used in dental radiography is small but Biologic damage does occur.

Back 14

Both statements are true

Front 15

What specific mechanism of radiation injury may result in the formation of hydrogen peroxide when xray energy is absorbed by patient tissues?

Back 15

Free radical formation created by the ionizing of water may occur

Front 16

Which of the following mechanisms of radiation injury may occur when xray energy is absorbed by patient tissues?

Back 16

Ionization and free radical formation

Front 17

Which is true regarding the direct theory of radiation injury?

Back 17

It involves a direct hit and absorption of an xray photon within a cell

Front 18

The indirect theory proposes that:

Back 18

Chapter 4 #5

Front 19

The quantity is of the xrays produced is controlled by the

Back 19

Milliamperage

Front 20

Milliamperage regulates the _ of electrons produced at the cathode filament

Back 20

Quantity

Front 21

Milliampere seconds is a combination of milliamperes and

Back 21

Exposure time

Front 22

Using 10 mA with an exposure time of 3 seconds would result in 30 mAs. If the milliamperage is increased to 15 the time must be decreased to _ seconds to maintain the same density of the exposed radiograph

Back 22

2

Front 23

In regard to increasing density

Back 23

Increase in either kVp or mA will increase density

Front 24

Which of the following changes will increase xray beam intensity?

Back 24

Source-to-film distance

Front 25

According to the inverse square law, the intensity of radiation is _ proportional to _ from the source of radiation

Back 25

Inversely; square of the distance

Front 26

According to the inverse square law, if the length if the PID is doubled the resultant beam is _

Back 26

PID doubled = one quarter

Front 27

Aluminum filters are used to remove _ energy _ wavelength X-rays.

Back 27

Low; longer

Front 28

According to the dose response curve when does and damage are plotted on a graph, a __ relationship is seen

Back 28

Linear, nonthreshold

Front 29

Which of the following is considered a short term effects radiation exposure

Back 29

Hair loss

Front 30

Ch 4 #17

Back 30

Ch4 #17

Front 31

A no threshold dose response curve suggests

Back 31

No matter how small the amount of radiation received, some biological damage occurs

Front 32

Stochastic Biologic effects from radiation:

Back 32

Occur as a direct function of dose

Front 33

Examples of nonstochastic effects include

Back 33

Erythema and loss of hair

Front 34

The _ radiation received and the _ the dose rate; the shorter the latent period

Back 34

More; faster

Front 35

Cellular injuries following the latent period may include (1) cell death (2) cessation mitoric activity and/or (3) abnormal mitoric activity.

Back 35

1,2,3

Front 36

_ refers to the quantity of radiation received or the total amount of radiation absorbed

Back 36

Total dose

Front 37

1) More radiation damage takes place with high dose rates (2) because a rapid radiation does not allow time for cellular damage to be required

Back 37

Both statements are true

Front 38

Which types if cells are more sensitive to radiation; (1) rapidly dividing (2) slowly dividing (3) young (4) old

Back 38

1 and 3

Front 39

Short term radiation effects are associated with:

Back 39

Large amounts of radiation absorbed in a short time and acute radiation syndrome

Front 40

Which of the following is considered short-term effect of radiation exposure?

Back 40

Hair loss

Front 41

__ is/are the single largest contributor to artificial radiation exposure

Back 41

Medical radiation

Front 42

Which of the following statements is/are true of the average dose of background radiation received by an individual in the United States

Back 42

The average dose ranges from 150 to 300 millirads and geographic areas at a higher elevation are associated with increased amounts of cosmic radiation

Front 43

The potential risk of dental radiography inducing a fatal cancer in an individual is about __ the risk of a person developing cancer spontaneously.

Back 43

1/1,000

Front 44

A 1 in 1 million risk of a fatal outcome is associated with the following activities

Back 44

All the choices

Front 45

Risk estimates suggest (1) that death is more likely to occur from common activities than from dental radiographic procedures and (2) cancer is much more likely to be unrelated to radiation exposure

Back 45

Both statements are true

Front 46

The use of F-speed film instead of D-speed film reduces the absorbed dose by __%

Back 46

60%

Front 47

Which of the following modifications in technique will reduce patient exposure to radiation during dental radiographic procedures?

Back 47

Longer source-to-film distance

Front 48

Which of the following combinations will result in the lowest absorbed dose for the patient from a 20-film series of dental radiographs

Back 48

Rectangular collimator with F speed film

Front 49

The fundamental unit of matter is:

Back 49

Atom

Front 50

The nucleus of an atom contains:

Back 50

Protons and neutrons

Front 51

What is true of somatic effects of irradiation?

Back 51

Changes are not transmitted to future generations

Front 52

Which subatomic particle carries a negative electrical charge?

Back 52

Electron

Front 53

Which of the following is true of orbits or the shells in the atom?

Back 53

K shell is the closest to the nucleus and has highest energy level

Front 54

Which of the following elements is the simplest atom which an atomic number of 1?

Back 54

Hydrogen

Front 55

The binding energy or binding force of an electron is?

Back 55

Weaker for electrons located in outer shells

Front 56

What is true of ionization?

Back 56

Gains an electron has a negative charge and atom loses and electron and has a positive charge

Front 57

An ion pair results when:

Back 57

Electron is removed from an atom

Front 58

Radiation is the emission and propagation of energy through space or a form of waves and particles (2) radioactivity can be defined as the process by which certain unstable atoms or elements undergo spontaneous disintegration to form a more balanced nuclear state

Back 58

Both are true

Front 59

Radioactivity is:

Back 59

The process by which certain unstable atoms or elements undergo spontaneous disintegration or decay in an effort to become more balanced

Front 60

What is true of ionizing radiation?

Back 60

Capable of producing ions by removing or adding an electron to an atom AND can be particulate or electromagnetic radiation

Front 61

Particulate radiations:

Back 61

Tiny particles of matter

Front 62

Which of the following types of cells is most radio sensitive?

Back 62

Blood

Front 63

Cathode rays are derived from which of the following types of particulate radiation?

Back 63

Electrons

Front 64

Which of the following types of particulate radiation are emitted from the nucleus of radioactive atoms?

Back 64

Beta particles

Front 65

Electromagnetic radiation

Back 65

Has no mass

Front 66

Which of the following forms of electromagnetic radiation are capable of ionization?

Back 66

X-rays

Front 67

Photons are

Back 67

Component of particle concept of electromagnetic radiation

Front 68

What is true of the wave concept of electromagnetic radiation?

Back 68

Frequency and wavelength are inversely related

Front 69

Which of the following forms of electromagnetic radiation has the shortest wavelength?

Back 69

Dental xray wave

Front 70

Which of the following components of the tubehead absorbs heat created by the production of X-rays?

Back 70

Insulating oil

Front 71

Which component aims and shapes the beam?

Back 71

PID

Front 72

Within the X-ray tube electrons are generated by the:

Back 72

Tungsten filament in the cathode

Front 73

Which of the following are considered radioresistant tissues?

Back 73

Salivary glands

Front 74

Purpose of the anode is to:

Back 74

Convert electrons into photons

Front 75

_ is the measurement of the number of electrons moving through a conductor

Back 75

Amperage

Front 76

Thermionic emission of the electrons occurs at the:

Back 76

Tungsten filament at the cathode

Front 77

Approximately what percentage of the kinetic energy of the electrons is converted to X-rays at the anode?

Back 77

Less than 1%

Front 78

The lead collimator

Back 78

Restricts the size of the xray beam

Front 79

What is true of general radiation?

Back 79

Also known as breaking radiation AND source of the majority of the X-rays that are produced

Front 80

Which form of the xray beam is most detrimental to the patient and operator?

Back 80

Primary radiation

Front 81

Which is the most common possibility when an xray photon interacts with matter?

Back 81

Compton scatter

Front 82

Which of the following four possibilities that can occur when an xray photon interacts with matter is responsible for producing densities on film that make dental radiography

Back 82

No interaction

Front 83

Critical organs exposed during dental radiographic procedures in the head and neck region include (1) skin (2) thyroid gland (3) lens of the eye (4) bone marrow

Back 83

1,2,3,4

Front 84

The traditional unit of dose is called:

Back 84

The radiation absorbed dose (rad)

Front 85

One gray is equivalent to _ rad(s)

Back 85

100 rads

Front 86

The SI equivalent if the rem is

Back 86

Sievert

Front 87

Naturally occurring background radiation includes:

Back 87

Cosmic and terrestrial radiation

Front 88

Uranium is an example of _ radiation

Back 88

Terrestrial