FINAL Flashcards by Amy Mitchell

What charge does the cathode/filament have?

Negative

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What charge do electrons have?

Negative

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What charge does the focusing cup have?

Negative

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What surrounds the filament/cathode?

Focusing Cup

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What does a dual focus cup contain?

2 Filaments 1 Anode

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Which focal spot would have the best spatial resolution small or large?

Small

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What charge does an Anode have?

Positive

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Anodes can be?

Stationary or Rotating

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How fast do Anodes spin?

3,000-10,000 RPM

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Which 2 metals can withstand a great amount of heat?

Graphite, Tungsten

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Which part of the x-ray tube is the stem and which part is outside of the X-ray tube. Stator and Rotor

Stator- Outside of the X-ray tube. Rotor- Stem

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When electrons strike the anode ____ energy is converted into heat and X-rays

Kinetic

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When electrons strike the anode, Kinetic energy is converted into __% heat __% X-ray

99% Heat 1% Xray

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Xray tube is made out of what type of glass?

Pyrex

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Why is the tube made out of pyrex glass?

To withstand heat

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Why is the X-ray tube vacuumed?

To provide unobstructed path for electrons

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What is the X-ray tube insulated with?

Lead and oil

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Leakage radiation cannot exceed?

100mR/hour at a distance of 1 meter

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German word for Braking?

Brehmsstrahlung

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What forms 85-90% of the beam?

Brems

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What occurs when electrons rapidly decelerate and loop around nucleus on surface of anode?

Brems

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What forms 10-15% of the beam

Characteristic Radiation

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What occurs when elections on face of anode drop to fill hole in inner shell?

Characteristic Radiation

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Used for fluoro requires positive pressure?

Deadman switch

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Tube current displays only during?

Exposure

Quantity, Number, Amount are controlled by?

mAs

Quality, Energy, Penetrating Ability, driving force are controlled by?

kVp

What kind of transformer has the least ripple(3-5%) is the most efficient?

High Frequency Transformer

What kind of motor is the X-ray tube?

Induction

No practical amount of _____ can ever compensate for inadequate ____

mA, kVp

Recorded detail is controlled by?

Small focal spot, Short/low OID , long/high SID

The smaller the angle the _____ the focal spot

Smaller

Projected or effective focal spot is smaller than actual focal spot

Line focus principle

Too high mas with too small focal spot

Blooming

FAT-CAT intensity of beam is greater on the cathode side of the tube

Anode Heel Effect

Put _____ part of anatomy under cathode end for anode heel effect

Thickest

3 ways to enhance anode heel effect?

Steep/small anode angle, large IR, short SID

Main purpose of filtration

Decrease patients skin dose

If tube operates at 70kv or above you must have at least _____ filtration

2.5mm AL

If tube operates at 60kV you must have _____ filtration

1.5 mm of AL

Amount of metal that cuts intensity to half its initial output

Half value layer

The thicker the half value layer the _____ the beam

Stronger

What kind of filter- thick part of filter at thin part of anatomy

Wedge/ trough

If you cut SID in half you get

4x greater radiation intensity

If you double the SID you....

Get 1/4 radiation intensity

What are two by products of the photoelectric effect

- photoelectron | - characteristic radiation

Total absorption of incoming photon. X-ray gives up all of its energy. Knocks out an inner shell electron ( know called photoelectron ) characteristic radiation released as electrons drop down to fill holes in shells.

Photoelectric effect

Photoelectric effect is what color?

Clear or White

What kV is classical?

Less than 30 kV

Modified scatter. X-rays gives up some but not all of its energy to knock out an inter she'll electron. Makes its presence known through scatter.

Compton

What are the 2 by products of Compton?

Compton or recoil electron. | Weakened X-ray photon

What color is Compton?

Gray

Pair production is

In pet scanning

Photo disintegration is

In radiation therapy

Absorption + Scatter =

Attenuation

When X-rays pass through without interacting with the atoms in the body.

Remnant/ exit radiation

Back on the radiograph

Remnant/transmission/Exit Radiation

Picture element that makes up the matrix?

Pixel

Larger matrix size and great number of pixels = better or worse spatial resolution?

Better

Optical density of 1/10

OD of 1/100

Density on film screen =

Brightness on digital

Recorded detail on screen film =

Spatial resolution on digital

Contrast on screen film =

Gray scale/ dynamic range on digital

what controls patient dose?

MAs

Density is the overall _______ of a radiograph

Darkness

Main controlling factor of density is?

Mas

To double density

Double mAs

To cut density in half

Cut mAs in half

If you add 15kv you must cut mas in half. If you - 15kv you must double mas

On 90kv and above

If you add 10kv you must cut mas in half if you -10kv you must double mas

Below 90

Scatter is?

Density

What controls scatter

If collimating decreases then density?

Increases

If collimating increases the density

Decreases

As part density increases IR density ____

Decreases

As part density decreases

IR density increases

Automatic processor (4)

Developer, fixer, washer, dryer

How long does an automatic processor take?

90 seconds

Main controlling factor of contrast?

Long scale low contrast has what kV?

High

Short scale, high contrast has what kind of kV?

Low kV

Increased grid ratio- increases contrast

Decreases scatter and density

Decreased grid ratio and decreased contrast

Increases scatter and density

Increased collimation = ______ contrast

Increased

Decreased collimation=______contrast

Decreased

Positive contrast ___ density

Adds

Negative contrast _____ density

Decreases

Fluid, edema, atelectasis, late stage Paget's disease

Increase kV

Emphysema, osteoporosis

Decrease kV

Size distortion=

Magnification

Increase SID and decrease OID to avoid

Magnification

Shape distortion

True distortion

Cause by mal-alignment of tube, part, and or IR.

Shape distortion/ true distortion

2 types of shape distortion/ true distortion

Elongation or forshortening

If "s" number is too high then the IR is?

Underexposed

If "s" number is too high then the IR is underexposed and image has excessive?

Quantum mottle/noise

If "s" number is too low then the IR IS?

Overexposed

If "s" number is too low then the IR is overexposed and patient may be ultimately overdosed due to?

Dose creep

Invisible image =

latent

Visible image =

Manifest

Lower the density the ____ the pixel pitch

Higher

The higher the density the _____ the pixel pitch

The lower the pixel pitch