X-Ray Physics

Front 1

speed of anode during x-ray production?

Back 1

3000-2500

Front 2

Concerning photons's wavelength?

Back 2

shorter wavelength the greater the energy

Front 3

high electric potential (kVp) is applied across the x-ray tube then the electrons are________to the anode

Back 3

attracted to

Front 4

kilovoltage controls the______
of the electrons to cathode flowing to the anode

Back 4

speed

Front 5

difference in taking a x-ray with or without grid is:

Back 5

non grid requires more KvP

Front 6

Because of unavoidable large oject film distance when taking a lateral or oblique cervical, magnification will be most reduced by using a focal film distance (FFD) of

Back 6

72 inches

Front 7

reason lateral or flexion/extension c-spin do not normally require grid?

Back 7

neck is typically smaller laterally

Front 8

you can identify the aspect of the x-ray tube that is the anode end of the tube because

Back 8

there are two main power supplying electrical cables

Front 9

as demostrated on a characteristic cirve, as film contrast decreases, film latitude

Back 9

increases

Front 10

the fixing chemistry usually contains

Back 10

Phenidone

Front 11

film latitude:

Back 11

meausre of the film's ability to record density and contrast over the useful range of optical denisty (OD) from .25 to 2.5

Front 12

x-ray photons:

Back 12

no rest mass and are neutral in charge

Front 13

electron binding energy:

Back 13

strength of electron attached to nucleus

Front 14

x-rays are considered part of particulate ionzing radiation
true or false

Back 14

false: electromagnetic radiation

Front 15

x-rays identified by their energy in the measured in:

Back 15

electron volts

Front 16

structures that absorb x-rays are called

Back 16

radioppaque

Front 17

muscular person needs higher kvp or lower kvp

Back 17

higher

Front 18

when performing an AP thoracic view: one should place the anode where?

What is this called?

Back 18

place the anode closest to the head and cathode away from patient

anode heal affect

Front 19

due to thickness of the abdomen in lateral dimension, a lateral x-ray projection of the lumbar spine requires:

Back 19

a moving or stationary grid

Front 20

requarding full spine radiography, due to the inherent non uniformity of part thickness, the best solution to create a more uniformly exposed x-ray would require the use of

Back 20

sectional filtration

Front 21

fixing solution will remain in the fixing solution____ as long as the developer

Back 21

200%

Front 22

grids are made of alternating strips of

Back 22

lead and radiulent material

Front 23

what are heat units

Back 23

kVp x mA x seconds

Front 24

added filtration what material is used

Back 24

aluminum

Front 25

intensifying screens for routine radiography would result in the least x-ray exposure to the patient?

Back 25

high plus

Front 26

primary purpose of added filtration at the x-ray tube is to:

Back 26

scatter the low energy x-rays before striking the patient

Front 27

magnification can be reduced by

Back 27

using shorter source/image distance

Front 28

poor film/screen contact results in

Back 28

a locally fuzzy image

Front 29

x rays travel:

Back 29

at the speed of light

Front 30

the intensity of the xray beam is

Back 30

greater on the side of the cathode

Front 31

an x-ray machine converts what percentage of available energy into x-rays

Back 31

1%

Front 32

kilovoltage (kvp) controls the penetrating power of the x-ray:

Back 32

photon

Front 33

what happens if kVp is too high?

Back 33

increased photons will cause white areas of the film to appear dark=diminished contrast

compton scatter radiaton will also be excessive=lacks contrast

Front 34

kvp too low?

Back 34

photons will not be able to penetrate the body=film lacks denisty and white film.

low kvp means higher MaS which means longer time of exposure=longer time.

patient absorbs more radiation

Front 35

lower kVp values are used for what body types

Back 35

extremities

Front 36

milliamperage (mA)

Back 36

describes the amount of electrical current flowing through the cathode filament during exposure.

The mA must complement the time of exposure to make adequate number of x-ray photon availabe to the film

Front 37

high mA=


lower mA=

Back 37

results shorter time of exposure

longer time of exposure

Front 38

variable kVp

Back 38

kilovoltage increases as size of body part increases and mAs values remain fixed for that body part.

problems:increasing compton interactions occurs in tissues.
Also, the scattered xray cannot be cleaned up by the grid and you get less contrast and film looks foggy

Front 39

fixed kV method:

Back 39

prefered method: maintains the contrast of the resulting film

Front 40

prefered method for x-ray technique

Back 40

fixed kV for given body part
vary mAs for each centimeter of thickness for every body part

Front 41

what would you do if patient was
muscular
child or osteopenia?

Back 41

normal mAs should be incrased a minimum of 50%

decrease mAs by 30%

Front 42

why the x-ray beam does not exhibit uniform intensity?

Back 42

due to the anode heel effect.

Front 43

how to deal with the heel effect

Back 43

use larger focal distance.

upright radiography make sure tube is directed toward standing patient.

have patient with thinner body part lie coser to anode

Front 44

what controls contrast?

Back 44

kVp and film type

Front 45

what determines detail?

Back 45

shortest object film distance
longest film distance
shortest exposure
film with best resolving power.

Front 46

longer focal film distance causes what to happen with time

Back 46

causes exposure time to be longer

Front 47

best resolving film-screen combinations are

Back 47

slowest and least sensitive to stimulation of the photons. (usually only for smaller extremites)

Front 48

obese patient needs lateral films: identify 3 ways to improve films

Back 48

1. patient compression (reduces patient exposure, reduce workload of x-ray tube)

2. mAs should be increased by 50%

3. longer focus distance: sharper image, less magnification and decreased patient dose.

using sectional filtration on lateral lumbar view uniformly expose the film from L1 to S1

Front 49

which factors control contrast of a film?

Back 49

kilovoltage peak (kVp)

Front 50

what are 4 things that need to be considered reguarding choice of exposure time?

Back 50

shortest practical time should be used
time of exposure could affect patient motion
logner times increase density
moving grids require exposure times of .1 seconds or more.

Front 51

mA station controls the

Back 51

electrical current passing through the filament