M1 - Radiographic Density

Brightness

_______ describes the concept of density as it displayed on a soft-copy monitor for digital images.

density

Brightness describes the concept of _____ as it displayed on a soft-copy monitor for digital images.

Characteristic Curve

________ is a graphical relationship between amount of exposure and resultant density on film.

Density

_______ is one of the two photographic properties that comprise visibility of detail.

Density

It is known as the degree of overall blackening from the black metallic silver deposited in the emulsion of film.

Visibility of Detail

__________ refers to the fact that the image is visible to the human eye only because sufficient density (and contrast) exists to permit the structural details to be perceived.

structural details

Visibility of detail refers to the fact that the image is visible to the human eye only because sufficient density (and contrast) exists to permit the _________ to be perceived.

Window level

_______ describes the digital processing that produces changes in density or brightness, so it also appropriate to use when controlling image density.

image density

Window level describes the digital processing that produces changes in density or brightness, so it also appropriate to use when controlling ________.

anatomical area of interest

The majority consideration in assessing density is verification that proper densities are visible throughout the ____________ on the image.

Common sense and a trained professional eye

_________ and _________ are the primary tools of the radiographer when evaluating density.

overexpose image

Whenever a choice must be made between excess and insufficient density, the wise decision is always the choice that will produce that ___________.

hot lamp, a hot spot, or a hot light

Overexpose image can be seen through a ______, ______, and ________.

30%

When unexpected density changes exceed the ______ necessary to become visible, they seldom place the image outside the acceptance limits.

outside

When unexpected density changes exceed the 30% necessary to become visible, they seldom place the image _____ the acceptance limits.

acceptance limits

When unexpected density changes exceed the 30% necessary to become visible, they seldom place the image outside the _______.

direct proportional one

While the relationship between mAs and exposure is a _________, the relationship of these 2 factors to density is much more complex.

D log E sensitometric curve or digital response curve

A ________ or a _________ expresses the relationship between exposure and density.

window levelling

For Digital Image Receptor systems, changes in mAs no longer control density. Image density or brightness on the display monitor is controlled by _______.

Digital Image Receptor

For __________ systems, changes in mAs no longer control density. Image density or brightness on the display monitor is controlled by window levelling.

Digital image histograms

__________ are graphic representations of the exposure to the image receptor.

mAs

______ is use as the primary controller of image receptor exposure and film density.

25%-35%

The minimum change necessary to cause a visible shift in density is 30% of mAs, or any other influencing factors that would equal this change. Various authors over the years have set the minimum for visibility change at values between ________ of mAs.

Kilovoltage

_________ alters the intensity of the beam reaching the image receptor in two ways.

kilovoltage

Therefore, a change in _______ alters the intensity of the beam when the mAs and other factors remain the same.

quantity and quality

Both the _____ and _______ of the x-ray beam will vary significantly with changes in kilovoltage.

4%-5%

_______ change in kVp in the lower ranges (30-50 kVp);

8%-9%

______ change is required in the middle ranges (50- 90 kVp);

10%-12%

_______ change in the higher ranges (90-130 kVp)

15 percent rule

Because the radiographer must have e method of using kilovoltage to adjust and compensate for film density changes, the rough guide known as the ___________ has been developed.

greater

Focal Spot Size – larger focal spots utilize a _______ incident electron stream than small focal spots.

higher milliamperages

Large focal spots tend to bloom more at _______ and may occasionally reach a point where they alter the image receptor exposure.

Anode Heel Effect

alters the intensity of radiation and therefore the density between the anode and cathode ends of the x-ray tube.

anode heel effect

The _________ is more pronounce when the collimator is open wide than when it is closed because of a greater portion of the peripheral beam

collimator

The anode heel effect is more pronounce when the _______ is open wide than when it is closed because of a greater portion of the peripheral beam

Anode Heel Effect

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

anode heel effect

The ________ may be converted to an advantage in examinations of objects with greater subject density at one end than at another.

inverse square law

Source-to- Image receptor Distance alters the intensity of the beam reaching the image receptor, according to the _______.

inverse square law formula

The _______ expresses the change in intensity when the distance changes.

moderate acceptance range

The exposure maintenance formula is only accurate within a __________.

50%

Distance doubling and halving will bring image receptor exposure within roughly _______ of the original exposure and usually within image acceptance limits

Filtration

its ability to alter beam intensity affect image receptor exposure and film density.

Beam Restriction

_________ - restricting the beam, collimating, or reducing the primary beam field size reduces the total number of photons available.

larger anatomical size and high starting kVp levels

Scatter production is dramatically increased with ________ and ________.

• Large anatomical part

• High kilovoltage

• Low grid efficiency

• Non grid examinations

Technical factor compensation for changes in film density is required only under the following circumstances:

patient

the _______ is the prime attenuator of the beam

anatomical part

the _______ being examined has a great deal of influence on image receptor exposure and film density.

inverse relationship

There is an _________ between tissue thickness or type and image receptor exposure or film density.

Grids

_______ absorb scatter, which would otherwise add exposure to the image receptor and density to the film.

contrast

Because the primary purpose of a grid is the improvement of _______, compensating for film density changes by varying the kVp is not recommended

Relative Speed (RS)

________ numbers are the most useful parameters for intensifying screen combinations.

decreases

As relative speed increases, the amount of exposure required to maintain the same film density _________.

increase

Film density will increase when the developer solution temperature increases, immersion time increases or replenishment rates _______.