Density Flashcards by MA. ANNE JARDINIANO

_______ and brightness refer to the same image quality attribute but are used and defined differently

DENSITY and brightness refer to the same image quality attribute but are used and defined differently

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relates directly to the amount of exposure received by the image receptor

radiographic density

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is the term used to describe images displayed on an x-ray film

density

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amount of blackening on the film

density

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the overall blackness on the processed image

density

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results from the development of the exposed silver bromide crystal from the film’s emulsion

density

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too dark - high density - ________

too dark - high density - OVEREXPOSED

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too light - low density - ____________

too light - low density - UNDEREXPOSED

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acceptable range of density units = 0._ to _ density units

acceptable range of density units = 0.25 to 2 density units

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60-80% of density is from ____

60-80% of density is from FOG

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visible change in density = ↑ density by __ to __%

visible change in density = ↑ density by 30 to 35%

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aerated tissue, fatty tissue, water, bone and teeth

tissue density

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instrument used to measure density

densitometer

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is the term used to describe images displayed on a computer monitor (digital images)

brightness

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it is the amount of luminance of a display monitor

brightness

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is the controlling factor of density because it directly alters the amount of radiation emitted by the tube

mAs

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factors that affect density but not brightness

film/screen system
processing

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factors affecting density and brightness

technical factors
patient
other factors

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3 under of technical factors

mas
kvp
sid

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5 under of film/screen system factors

film speed
screen speed
phosphor grain size
phosphor layer thickness
phosphor concentration

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3 under of processing factors

development time
developer temperature
developer replenishment rate

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other factors affecting density/brightness

filtration
collimation
grid
heel effect
fog
voltage waveform

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density is directly controlled by ___

density is directly controlled by mAs

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↑ mAs = _ exposure = _ density

↑ mAs = ↑ exposure = ↑ density

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mAs is governed by the _________ law

mAs is governed by the RECIPROCITY law

law that states any combinations of mA and time that produce the same mAs value will produce the same density

reciprocity law

law that states overall density on a radiograph is proportional only to the total energy imparted to the radiographic film

reciprocity law

mAs influences focal spot blooming ↑ tube current = ↑ actual focal spot size

mAs influences focal spot blooming ↑ tube current = _ actual focal spot size

directly affects density through production of ____

directly affects density through production of FOG

fog ↑ kVp = _ supplemental density

↑ kVp = ↑ supplemental density

fog ↓ kVp = _ supplemental density

↓ kVp = ↓ supplemental density

kVp penetrating ability ↑ kVp = _ wavelength = _ penetrability

kVp penetrating ability ↑ kVp = ↓ wavelength = ↑ penetrability

kVp penetrating ability ↓ kVp = _ wavelength = _ penetrability

↓ kVp = ↑ wavelength = ↓ penetrability

affects the production of scattered radiation affects exposure to patient affects number of remnant x-rays exiting the patient to strike the image receptor

penetrating ability

intensity of the x-ray beam is inversely proportional to the square of the distance between the source of x-rays and the image receptor

inverse square law

intensity is measured in _________ (traditional) or _________ (SI)

intensity is measured in ROENTGENS (traditional) or COULUMBS/KILOGRAM (SI)

inverse square law if SID is ↑ 2x = intensity/density _4x if SID is ↓ ½ = intensity/density _4x

inverse square law if SID is ↑ 2x = intensity/density ↓4x if SID is ↓ ½ = intensity/density ↑ 4x

variation in intensity is the result of the divergence of the x-ray beam as it travels through space

inverse square law

Grids ↓ scatter radiation striking the image receptor ↓ grid ratio = _ density ↑ grid ratio = _ density

Grids ↓ scatter radiation striking the image receptor ↓ grid ratio = ↑ density ↑ grid ratio = ↓ density

generally, use of grids = _ fog = _ density

generally, use of grids = ↓ fog = ↓ density

faster screen/film combination = _ density

faster screen/film combination = ↑ density

direct exposure technique = _ density

direct exposure technique = ↓ density

beam restriction ↑ beam restriction = _ scatter radiation = _ fog = _ = density

↑ beam restriction = ↓ scatter radiation = ↓ fog = ↓ = density

beam restriction will _ density by limiting the area of the patient being struck by x-rays

beam restriction will ↓ density by limiting the area of the patient being struck by x-rays

beam restriction ↓ field size = _ area of production of scatter fog = _ density

↓ field size = ↓ area of production of scatter fog = ↓ density

negligible effect on density; its purpose is primarily for radiation protection

filtration

has an impact on contrast because the average wavelength of the filtered beam is shorter than the nonfiltered beam

filtration

___________ _______ even out density of irregular anatomy

COMPENSATING FILTERS even out density of irregular anatomy

anatomy affects density through: variation of _ variation of tissue ______ and ______

anatomy affects density through: variation of Z variation of tissue density and thickness

________ ________affect density by either altering the Z or altering the tissue integrity, density and thickness

PATHOLOGIC CHANGES affect density by either altering the Z or altering the tissue integrity, density and thickness

additive pathologies ↑ x-ray absorption in tissue = needs _ in kVp

additive pathologies ↑ x-ray absorption in tissue = needs ↑ in kVp

ADDITIVE aortic aneurysm, aortic acne, ascites, cirrhosis, hypertrophy

abdomen

ADDITIVE atelectasis, CHF, osteoblastic metastases, pleural effusion, pneumonia

chest

ADDITIVE hydrocephalus, osteochondroma, late stage Paget’s disease

skeleton

ADDITIVE abscess, edema, sclerosis

non specific

destructive pathologies ↓ x-ray absorption in tissue = needs _ in kVp

destructive pathologies ↓ x-ray absorption in tissue = needs ↓ in kVp

DESTRUCTIVE bowel obstruction, free air

abdomen

DESTRUCTIVE bowel obstruction, free air

abdomen

DESTRUCTIVE emphysema, pneumothorax, active TB

chest

DESTRUCTIVE gout, osteolytic metastases, multiple myeloma, early stage Paget’s disease, osteoporosis, degenerative arthritis, osteoporosis

skeleton

DESTRUCTIVE atrophy, necrosis, emaciation, malnutrition

non specific

the anode heel effect is emphasized under the following conditions: at _ SIDs with _ cassette size with _ anode angle x-ray tubes

the anode heel effect is emphasized under the following conditions: at ↓ SIDs with ↑ cassette size with ↓ anode angle x-ray tubes

x-rays are absorbed by the “heel” of the anode anode side – __% cathode side – ___% difference – __%

x-rays are absorbed by the “heel” of the anode anode side – 75% cathode side – 120% difference – 45%

______ ______ should be placed under the cathode side of the x-ray tube to take advantage of the anode heel effect

THICKER ANATOMY should be placed under the cathode side of the x-ray tube to take advantage of the anode heel effect

↑ SID = _ anode heel effect ↓ field size = _ anode heel effect ↑ anode angle = _ anode heel effect

↑ SID = ↓ anode heel effect ↓ field size = ↓ anode heel effect ↑ anode angle = ↓ anode heel effect

PROCESSING ↑ developer temperature (2-3°F) = _ density ↑ development time = _ density ↑ replenishment rate = _ density

↑ developer temperature (2-3°F) = ↑ density ↑ development time = ↑ density ↑ replenishment rate = ↑ density