Technique Ch. 26

Front 1

Image receptor (IR) exposure

Back 1

One of the 2 photographic properties that comprise visibility of detail. In digital imaging it is the critical quality factor to assess and comparable to density in the film / screen environment

Front 2

Brightness

Back 2

The concept of density as it is displayed on a softcopy monitor for digital imagesNot the same as density

images

imagesNot the same as density

Not the same as density

Front 3

Window level

Back 3

The digital processing that produces changes in density / brightness

Describes digital post-processing that produces changes in brightness, so it is appropriate to use when controlling the display of an image

Front 4

IR exposure and contrast

Back 4

What are the two photographic properties that allow detail to be seen on radiographic images

Front 5

IR exposure

Back 5

The term density was replaced when using digital with the term _____, because film is no longer the primary image receptor

Front 6

Exposure Indicator (EI) values

Back 6

With digital imaging, the key to a visible image is having the correct IR exposure, which is best evaluated using the

Front 7

Overexposed image

Back 7

The IRS has received too many photons and, as a result, has recorded too much information

Black

Front 8

Underexposed image

Back 8

Has not received the information and is not capable of being manipulated to reveal details that were never recorded using digital post processing

White

Front 9

Digital post processing

Back 9

Can eliminate the excess information of an overexposed image and reveal details within the range of human visual ability, producing a visually acceptable image

Front 10

Quantum mottle/noise

Back 10

In radiography, a speckled, snowy looking, non-uniform ___ caused by an insignificant number of X-ray photons striking the radiographic image receptor during an exposure. The _____ is corrected by increasing mAs

Front 11

Quantum noise

Back 11

A lack of significant incoming data to process an image. Also known as quantum mottle

Can be corrected by increasing mAs

Front 12

System noise

Back 12

Electronic components within the digital image receptor can also add noise to the image, known as

Front 13

Ambient noise

Back 13

background radiation also contributes to image noise and results in

Front 14

Film screen systems

Back 14

With ______, mAs was considered to be the controlling factor for IR exposure. With digital systems, this is no longer true

Front 15

Influencing factors affecting IR exposure

Back 15

Front 16

Linear, non-linear

Back 16

Digital receptor have a ___ response to exposure while film has a ____

Front 17

30%

Back 17

Minimum percent change in mAs for Visible density change

Front 18

Doubles or halfs

Back 18

The general rule of thumb for mAs changes is to make adjustments in increments of

Hint 18

A repeated image that is underexposed at 10 mAs should be repeated at 20, 40, or 80 mAs, depending on the circumstances

Front 19

Repeating

Back 19

Less than 30% change in mAs seldom justifies..

Front 20

KVp

Back 20

Controls average energy of X-ray photons at anode Target

Affects production of scatter radiation

Front 21

IR exposure and film density

Back 21

Both the quantity and quality of the X-ray beam will vary significantly with changes in kVp. As a result, kVp has a tremendous impact on

Front 22

15% rule

Back 22

is used as a guide to maintain the same IR exposure when kilovoltage changes.This increase in kilovoltage causes a doubling of exposure to the IR.

This increase in kilovoltage causes a doubling of exposure to the IR.

This increase in kilovoltage causes a doubling of exposure to the IR.

Front 23

15% rule

Back 23

A radiograph of the elbow is produced using a 4 mAs at 60 kVp. What kVp would be required to halve the exposure to the IR?

Front 24

kVp

Back 24

Can influence the shape of the histogram

Front 25

KVp change

Back 25

_______ is not recommended to control image noise

Front 26

4-5% , 10-12%

Back 26

A change in IR exposure can usually be detected with a

__ to __% change in kvp in lower ranges (30-50 kVp)

and

__ to __% change in higher ranges (90-130 kvp)

Front 27

Contrast

Back 27

Significant changes in kVp can impact

Front 28

mAs

Back 28

Primary influencing factor to IR exposure

Front 29

Total exposure to the image receptor

Back 29

Image quality is a function of

Front 30

Quantum noise

Back 30

Is the largest contributor to total noise

Front 31

mAs

Back 31

Is Primary IR exposure controlling factor

Directly proportional to exposure

Marginal noise on image generally requires a 30% increase in exposure

Front 32

Focal spot size

Back 32

Larger _____ utilize a greater incident electron stream then smaller ones.

Will not affect density / IR exposure in properly calibrated equipment.

Blooming results from high mAs selection.

Proper calibration on a regular basis keeps focal spot issues controlled.

Calibrated systems with continued blooming, may warrant x-ray Tube replacement

Hint 32

Front 33

Anode heel effect

Back 33

Alters the intensity of radiation, and therefore the IR exposure, between the anode and cathode ends of the X-ray tube.

Front 34

Anode heel effect

Back 34

Alters intensity of beam across cathode anode access.

IR exposure up to 45% greater at cathode side of beam

Always place thicker side of body part on cathode side

Hint 34

Front 35

Anode Heel Effect

Back 35

More pronounced with wider collimation.

This effect is minimized by collimating the beam and eliminating as much of the intensity difference at the periphery as possible

Hint 35

Front 36

Exposure maintenance formula (distance)

Back 36

To maintain IR exposure, mAs (or an influencer) must be changed to compensate for the exposure changeThis formula is used because mAs must increase when distance increases, and vice versa in order to maintain ion exposure

This formula is used because mAs must increase when distance increases, and vice versa in order to maintain ion exposure

This formula is used because mAs must increase when distance increases, and vice versa in order to maintain ion exposure

This formula is used because mAs must increase when distance increases, and vice versa in order to maintain ion exposure

This formula is used because mAs must increase when distance increases, and vice versa in order to maintain ion exposure

This formula is used because mAs must increase when distance increases, and vice versa in order to maintain ion exposure

Front 37

Inverse Square law (Distance)

Back 37

SID altars the intensity of the beam reaching the IR, according to this law.

The law states that the intensity exposure varies inversely with the square of the distance.

For example, as distance increases, radiation intensity and IR exposure decrease

Front 38

OID (distance)

Back 38

Has an effect on IR exposure.

The air gap technique uses an increased OID to prevent scatter radiation from reaching the IR.

By increasing OID using the air gap technique, scatter that would normally strike the IR will miss the receptor, causing a decrease in IR exposure

Front 39

Filtration

Back 39

Has the ability to alter beam intensity affect IR exposure.

IR exposure decreases when this increases

Increased _____ increases average energy of beam but reduces intensity of beam (quantity)

Front 40

Beam restriction (collimation)

Back 40

Reducing the primary beam field size reduces the total number of photons available.

This reduces the amount of scatter radiation and therefore reduces the overall IR exposure

Reduces scatter and secondary radiation (remnant) striking IR

Dramatic changes in this require mAs compensation

Front 41

Decreases IR exposure

Back 41

Increased beam restriction does what to IR exposure

Front 42

Anatomical part

Back 42

The amount of attenuation is dependent on the thickness and type of the tissue being imaged.

Tissue type is affected by the atomic number and density of tissue

The use of contrast media will alter the atomic number and affect IR exposure.

Pathologically can alter tissue thickness and or type, affecting IR exposure

Inverse relationship between IR exposure and part thickness tissue density

As tissue thickness, average atomic number of the tissue, and / or tissue density increases, IR exposure decreases

Front 43

Pathology

Back 43

Can have either an additive or destructive effect.

Additive conditions (radioplaque) decrease IR exposure.

Destructive conditions (radiolucent) increase IR exposure

Front 44

Grids

Back 44

_____ absorb scatter, which would otherwise be exposure to the IR and density to the film.

The more efficient the ______, the less will be the IR exposure.

_____ with high ratios, low frequencies, and dense interspace material, moving grids, and improperly used grids, all reduce IR exposure

_____ with high ratios, low frequencies, and dense interspace material, moving grids, and improperly used grids, all reduce IR exposure

Front 45

Image receptors

Back 45

Front 46

Brightness

Back 46

Is the proper term for the Luminous intensity (measured in candela) of the display monitors light emission