Chapter 3 : Radiation Characteristics

Question 1

The term “quality” in dental imaging

Answer 1

the energy or penetrating ability of the xray beam

Question 2

Voltage

Answer 2

measurement of force of the potential difference between two electrical charges

Question 3

When voltage is increased the speed of the electrons is ______

Answer 3

increased

Question 4

when the electrons strike the target with greater force and energy, what resutls?

Answer 4

penetrating xray beam with a short wavelength

Question 5

Measurement of Voltage

Answer 5

Volts (v) or kilovolts (kV)

Question 6

1 kV equals

Answer 6

1000 volts

Question 7

Kilovoltage

Answer 7

Maximum voltage of an alternating current

Question 8

the use of higher kV produces what?

Answer 8

more penetrating xrays

with greater energy

Question 9

current intra oral settings in kV range

Answer 9

60-70kV

Question 10

regulates the speed and energy of the electrons and determines penetrating ability of xray

Answer 10

quality

Question 11

Density

Answer 11

overall darnkess or blackness of an image

Question 12

if the kV is decreased the resultant image exhibits a _____ density and appears _____

Answer 12

decreased

lighter

Question 13

increased kV = _____ density (darker)

Answer 13

increased

Question 14

contrast

Answer 14

differences of dark and light areas in an image

Question 15

an image with “high contrast” has many ____ areas _____ areas and few shades of ______

Answer 15

black
white
grey

Question 16

an image with “low contrast” has many shades of ______ instead of areas that are predominently ______ and _____

Answer 16

grey
black
white

Question 17

exposure time

Answer 17

interval of time during which xrays are produced

Question 18

impulse

Answer 18

measurement that refers to the fact that xrays are created in a series of bursts or pulses rather than a continous stream

Question 19

one impluse occurs every _/__ of a second

Answer 19

1/60

Question 20

kilovoltage and _______ are inversely related

Answer 20

exposure time

Question 21

Quantity of the xray beam

Answer 21

number of xrays produced in the dental xray unit

Question 22

amperage

Answer 22

measurement of the amount of electrons passing through the cathode filament

Question 23

ampere (A)

Answer 23

measures number of electrons, or current flowing in the cathode filament.

Question 24

One milliamperage (mA)=

Answer 24

1/1000 of an ampere

Question 25

What does the milliamperage regulate?

Answer 25

temperature of the cathode filament

Question 26

an increase in the number of electrons that strike the anode ,_______ the number of xrays emitted from the tube

Answer 26

increases

Question 27

how does milliamperage effect the density of an image

Answer 27

when mA is increased, the overall density also increases which results in a darker image.

Question 28

increased mA = ____ density & ___ image

Answer 28

higher | darker

Question 29

KLMN

Answer 29

Kv=quaLity | Ma=quaNtity

Question 30

higher kV= ____ exposure time

Answer 30

decreased

Question 31

lower kV = _____ exposure time

Answer 31

increased

Question 32

increased mA=______ exposure time

Answer 32

decreased

Question 33

decreased mA= ____ exposure time

Answer 33

increased

Question 34

intensity

Answer 34

product of the quantity AND quality per unit of area per unit of time exposure

Question 35

regulates the penetrating power of the xray beam by controlling the speed of the electrons while travelling between the cathode and anode

Answer 35

kilovoltage

Question 36

controls the penetrating power of the xray beam by controlling the number of electrons PRODUCED in the xray tube and the number of xrays produced.

Answer 36

milliamperage

Question 37

as with mA this also affects the number of xrays produced

Answer 37

exposure time

Question 38

target surface distance

Answer 38

distance from the source (tungsten target in anode) of radiation to the patients SKIN

Question 39

target object distance

Answer 39

distance from the source (tungsten target in anode) of radiation to the tooth

Question 40

target-receptor distance

Answer 40

distance from the source (tungsten target in anode) of radiation to the receptor

Question 41

as x rays travel away from their source of origin, the intensity of the beam _____

Answer 41

lessens

Question 42

The inverse square law

Answer 42

the intensity of radiation is proportional to the square of the distance from the source of radiation

Question 43

according to the inverse square law, when the target receptor is doubled, the resultant beam is __/__ as intense and when the target receptor distance is REDUCED by HALF, the resultant beam is ___ times as intense

Answer 43

1/4 four

Question 44

The thickness of material (aluminum) that, when placed in the path of the x-ray beam, reduces the exposure rate by one-half.

Answer 44

half value layer (HVL)

Question 45

If an xray beam as an HVL of 4 mm, a thickness of __ mm would be necessary to decrease its intensity by half

Answer 45

4