Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/56

Click to flip

56 Cards in this Set

  • Front
  • Back

Along with contrast allows detail to be seen

Density

Degree of blackening from black metallic silver deposition on film

Film density

Adjustable component at the monitor, represents how much light is being emitted from the monitor, window level, changes overall lightness and darkness of image

Brightness

To much density is ___, to much information recorded, to much penetration, to bright or light

Overexposed

To little density is ___, to much beam attenuation, diagnostic info did not reach IR

Underexposed

Multiple variables influence __ thereby influencing image __

Exposure, density

Primary adjustor, exposure determines density, directly proportional, controls density,

mAs

As mAs goes __ exposure goes __ proportionally, so density goes __

Up, up, up

Digital is always a __ relationship

Linear

Film is linear only along the __ part of the D log E curve only

Straight line

mAs reciprocity

Exposure=intensity x time

Intensity of exposure

mA

Length of exposure

Time

Depends on exposure but independent of the components

Density

Interchange __ and ___ as long as __ is the same, ___ will be the same

mA, time, mAs, density

Occurs at extremely short or long exposure, inadequately calibrated equipment

Reciprocity failure

The 30% guideline is for __ only

Film

Why do you have to change mAs by at least 30% on film

Can only see a visible change after changing mAs by 30%

Why does the 30% guideline not apply to digital

The histogram will control small to fairly large density adjustments

If density needs adjustment on film what do you do

Double the mAs to make darker, cut mAs in half to make lighter, anything less image does not need repeating

With digital systems typically mAs adjustments will only need to be ___ to correct quantum mottle

Increased

On digital what will tell you if technique can be decreased next time around

EI#

If kVp goes up, scatter goes __, so density goes __

Up, up

If kVp goes up, penetrability goes __, so density goes __

Up, up

If kVp goes up,# of interactions at the target goes __, so __ xray photons are produced (quantity)

Up, more

Affects quantity and quality

kVp

Preferred method for density adjustments is through

mAs

Non linear relationship between a change in __ and __

kVp, density

Increase the kVp by 15% to double exposure to the IR, and cut mAs in half, will affect image contrast, influenced by tissue type, *more effectively use when a change in contrast is needed

15% rule

What kVp range does the 15% rule work best

60-100 kVp

With the same technique if a large focal spot is used and then a small focal spot what should not change

Density

What side of the is beam intensity greater

Cathode

This describes the change in exposure intensity when distance change

Inverse square law

change SID but keep same exposure what do you use

Direct square law

Going from 40" to 56" what would you do to mAs

Double

From 72" to 56"

Halve

From 40" to 72"

Double then double again, should put exposure with in 50% range of pervious

This type of filtration reduces exposure by eliminating soft xrays

Inherent/added

Type of filter that affects IR exposure and therefore density

Compensating

As beam restriction increases (FOV gets smaller) IR exposure will __

Decrease

Will reduce the number of photons, reduce scatter and patient dose

Collimating

Affects beam attenuation, inverse relationship with density, non linear relationship with density

Tissue thickness, atomic #, tissue density (amount of atoms in area)

Radiopaque like Ba or I, positive or negative contrast

Positive

Radiolucent like air or gas, positive or negative contrast

Negative

__ has similar effective atomic # as fat and water

Air

Larger tube angles create __ parts

Thicker

What absorbs scatter

Grids

The characteristics of IRs such as phosphor sensitivity will influence photon energy absorption and therefore IR __

Exposure (and density)

With digital post processing has a greater influence on what you __

See

With film what indicates how much xray energy is needed to achieve an exposure for a given speed cassette

Speed numbers

Film density will also be affected by (this is most overlooked)

Processor chemicals

Developer concentration to high, film in developer to long, developer temp to high

Increased film density

Processor chemicals contaminated, and become less effective

Decreased density

With digital what indicates how much exposure the IR received

EI#

There is greater __ with digital

Latitude

Enough __ is needed for the computers __ to adjust the information into the visible range

Exposure, histogram