Characteristics of a radiographic image

Question 1

what is radiographic density?

Answer 1

overall degree of darkening

Question 2

what is radiographic contrast?

Answer 2

describes range of densities on the radiograph

Question 3

what is spatial resolution?

Answer 3

ability to distinguish separate objects that are close together

Question 4

what is image sharpness?

Answer 4

ability to define an edge

Question 5

what is geometric distortion?

Answer 5

limitation of 2D planar imaging (change in size or shape of image)

Question 6

How would you increase density?

Answer 6

increase kVp, ma, or s

Question 7

what occurs when you increase exposure?

Answer 7

increase density/darkening

Question 8

The useful range of film is represented by –

Answer 8

a narrow range of radiation exposure

Question 9

enamel appears brighter because x-ray –

Answer 9

is not hitting air

Question 10

maxillary sinus appears darker because x-ray is –

Answer 10

hitting air

Question 11

W/o changing anything how would x-ray of a child appear like?

Answer 11

darker (more photons)

Question 12

How would you adjust for an osteoporotic patient?

Answer 12

lower density (less radiation/photons)

Question 13

high contrast =

Answer 13

short gray scale

Question 14

image is a – that were received

Answer 14

map of photons

Question 15

How would you adjust contrast to view caries (demineralization)?

Answer 15

high contrast

Question 16

How would you adjust contrast to full extent of a lesion on a bone?

Answer 16

low contrast (more gray to see how far it permeates)

Question 17

effect of increasing kVp on contrast

Answer 17

decreases contrast (more photons thru patient)

Question 18

effect of decreasing kVp on contrast

Answer 18

better contrast but harmful as more energy absorbed in patient

Question 19

effect of scatter on contrast

Answer 19

reduce contrast

Question 20

effect of collimation on contrast

Answer 20

reduce scatter –> better image and for patient

Question 21

photons penetrated/absorbed

Answer 21

signal

Question 22

scattered radiation

Answer 22

noise

Question 23

which exposure factors have no effect on contrast?

Answer 23

mA and s

Question 24

lead is radiopaque so it will appear –

Answer 24

white

Question 25

plastic is radiolucent so it will appear --

Answer 25

dark

Question 26

how would you adjust focal spot size for a good spatial resolution?

Answer 26

small

Question 27

increased patient or receptor movement could cause --

Answer 27

blur

Question 28

sharpness and spatial resolution are influenced by

Answer 28

receptor, motion, focal spot size

Question 29

which factors can you control?

Answer 29

density, contrast, resolution