Chapter 8: Dental xray Image characteristics

Question 1

A structure that appears _______ lacks density and permits the passage of the x-ray beam with little or no resistance.

Answer 1

radiolucent

Question 2

refers to that portion of an image that appears light or white.

Answer 2

Radiopaque

Question 3

provides a great deal of information; the images exhibit proper density and contrast, are of the same shape and size as the object exposed, and have sharp outlines.

Answer 3

diagnostic image

Question 4

Two visual characteristics that directly influence the diagnostic quality of a dental image.

Answer 4

density and contrast

Question 5

three exposure factors control the density of a dental image, as follows:

Answer 5

kilovoltage
milliamperage
exposure time

Question 6

higher mA = ____ density = darker

Answer 6

higher

Question 7

higher kV = _______ density

Answer 7

higher

Question 8

higher exposure time = _______ density

Answer 8

higher

Question 9

higher subject thickness = _______ density

Answer 9

lower

Question 10

higher kV=_______ scale contrast

Answer 10

long scale contrast

Question 11

lower kV= _______ scale contrast

Answer 11

short scale contrast

Question 12

If the kilovoltage is increased, the density increases, and the image appears __________

Answer 12

darker

Question 13

if kilovoltage is decreased, the density decreases, and the image appears ___________

Answer 13

lighter

Question 14

Density is directly related to ______ ____

Answer 14

exposure time

Question 15

An image that does not have very dark and very light areas but instead has many shades of gray demonstrates ______ _____ .

Answer 15

low contrast

Question 16

When viewed on a light source, a dental image that has very dark areas and very light areas demonstrates ____ ______

Answer 16

high contrast

Question 17

refers to the characteristics of the film that influence radiographic contrast

Answer 17

film contrast

Question 18

Development time or the temperature of the developer solution affects the contrast of a dental radiograph. For example, an increase in development time or developer temperature results in a film with high contrast. TRUE OR FALSE

Answer 18

TRUE

Question 19

subject contrast

Answer 19

characteristics of the subject that influence radiographic contrast.

Question 20

X-rays with higher energy are better able to penetrate tissue. T or F

Answer 20

True

Question 21

A dental image that shows only two densities, areas of black and areas of white has a ___ _____ scale

Answer 21

short contrast scale

Question 22

An image that exhibits a short contrast scale can also be described as having high contrast, in which the _____ and ______ areas are easily distinguished from each other

Answer 22

black and white

Question 23

A dental image that exhibits many densities, or many shades of gray, has a ____ _____ scale

Answer 23

long contrast scale

Question 24

A device known as a _______can be used to demonstrate short-scale contrast and long-scale contrast.

Answer 24

stepwedge

Question 25

used to monitor the qualities of the film, the film processing, and the digital sensor, as well as calibration of the x-ray machine

Answer 25

stepwedge

Question 26

Three geometric characteristics that influence the diagnostic quality of a dental image :

Answer 26

sharpness magnification distortion

Question 27

(also known as detail, resolution, or definition) refers to the capability of the receptor to reproduce the distinct outlines of an object

Answer 27

sharpness

Question 28

unsharpness, or blurring, of the edges.

Answer 28

penumbra

Question 29

The sharpness of an image is influenced by the following three factors:

Answer 29

focal spot size film composition movement

Question 30

the tungsten target of the anode serves as a ____ ____ this small area converts bombarding electrons into x-ray photons.

Answer 30

focal spot

Question 31

The size of the focal spot ranges from _____ to _____

Answer 31

0.6 , 1.0 mm

Question 32

The smaller the focal spot area, the ______the image; the larger the focal spot area, the greater the loss of ____ _____

Answer 32

sharper image sharpness

Question 33

The composition of the film emulsion influences sharpness. T or F

Answer 33

TRUE

Question 34

refers to a radiographic image that appears larger than the actual size of the object it represents.

Answer 34

magnification

Question 35

Magnification, or enlargement of a radiographic image, results from the diverging x-ray beam. TRUE OR FALSE

Answer 35

TRUE

Question 36

The magnification on a dental image is influenced by the following:

Answer 36

target receptor distance object- receptor distance

Question 37

target receptor distance

Answer 37

distance between source of xrays and the image receptor

Question 38

which PID results in less image magnification? Longer PID or shorter PID

Answer 38

longer PID and target receptor distance. Longer PID limits magnification

Question 39

Object receptor distance

Answer 39

distance between the object being radiographed and the image receptor

Question 40

A decrease in object-receptor distance results in a decrease in magnification, and an increase in object-receptor distance results in an increase in image magnification . T OR F

Answer 40

TRUE

Question 41

distortion of a radiographic image is a variation in the true size and shape of the object being radiographed. This type of image does not have the same size and shape as the object being radiographed .

Answer 41

distortion

Question 42

The dimensional distortion of a radiographic image is influenced by the following

Answer 42

Object receptor alignment x-ray beam angulation

Question 43

To minimize dimensional distortion, the object and receptor must be______ to each other.

Answer 43

parallel

Question 44

To minimize dimensional distortion, the x-ray beam must be directed ________to the tooth and the receptor.

Answer 44

perpendicular

Question 45

Of the three exposure factors only the ______ has a direct influence on contrast

Answer 45

Kilovoltage