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Radiology Bushong > Test 6 Ch 17-18 > Flashcards

Test 6 Ch 17-18 Flashcards

1
Q

Spatial frequency is measured in

A

Line pairs

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2
Q

2 very important image properties!! ?

A

Spatial resolution

Contrast resolution

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3
Q

The ability to render small objects on an image

A

Spatial resolution/MTF

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4
Q

Are soft tissues like liver high or low frequencies??

Are bones, breast, vessels high or low frequencies??

A

Low spatial frequencies
Easy to image

High spatial frequencies
More difficult to image

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5
Q

No digital imaging system can image an object smaller than?

A

1 pixel

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6
Q

What is MTF?

A

Modulation transfer function

MTF curve graphs show- low spatial frequency=large objects

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7
Q

Single screen and smaller focal spot result in better spatial resolution in?

A

Mammography

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8
Q

Th ability to distinguish many shades of gray from white to black

A

Contrast resolution

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9
Q

Dynamic range is ??

A

Gray scale

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10
Q

Viewers can only visualize dynamic range up to??

A

30 shades of grey

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11
Q

Digital systems have different dynamic range such as
MRI n CT-
DR-
DM-

A

12 bit
14 bit
16 bit

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12
Q

Image contrast change

Human eye sees 30 shades of grey

A 
Post processing 
(Window and level)
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13
Q

Radiographers strive for ______ SNR

A

High

Signal noise ratio -
mAs increased than SNR is increased =higher patient dose

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14
Q

Image detail (spatial resolution is determined by ?

A

MTF

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15
Q

Contrast resolution is improved with ________ mAs

A

Higher

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16
Q

What modality is the best contrast resolution system??

A

CT

Bcuz of collimation and scatter reduction

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17
Q

Technique creep should replace dose creep meaning ??

A

Lower mAs an increase KvP on certain body parts

18
Q

A measure of X-ray absorption efficiency

A

DQE

Detective quantum efficiency

19
Q

The basic photo metric unit

A

Lumen

20
Q

The fundamental quantity of photometry ___________

This is the total intensity of light from a source

A

Luminous flux

21
Q

One lumen of luminous flux incident on a single square foot is a ??

A

Foot candle (ft)

22
Q

A property of a source of light

Measured in ??

A

Luminance intensity

Candela

23
Q

Two fundamental square laws associated with photometry ?

A

Inverse square law

Cosine law

24
Q

A measure of brightness

Measured in ?

A

Luminance

A nit

25
Q

Soft copies are viewed on ??

A

Cathode ray tube

LCD

26
Q

Bright light/ effects cones of eye

Dim light/effects rods of eye

A

Photopic

Scotopic

27
Q

Illuminates the pixel and is blocked or transmitted by the orientation of the liquid crystals

A

Backlight

28
Q

A measure of image luminance or LCDs ?

A

Aperture ratio

29
Q

A medical flat panel is ___________

A

Monochrome

30
Q

Electroluminenscence

Or light emitting diode (LED)

A

A diode that is an electronic device that allows current flow in one direction

31
Q

Active matrix and pixels

Is flat faced

A

LCD

32
Q

An LEDs purpose is to not replace the LCD but rather be the

A

Backlight for such a monitor

33
Q

LEDs have many advantages such as??

A

Lower power use
Thinner in size
Longer life

34
Q

Preprocessing provides electronic calibration to reduce pixel to pixel.. and this is done manually or electronically??

A

It is automatic!!

35
Q

The preprocessing calibration techniques are identified as

A

Flat shielding

36
Q

What is ambient light??

A

The light we have before a light is turned on.

37
Q

Makes white-black and black-white

See changes in anatomy
Removing anatomy

A

Image inversion

Subtraction (DSA)

38
Q

Effective for small fractures and hug contrast tissues

A scanned beam
Is curved faced

A

Edge enhancement

Cathode ray tube (CRT)

39
Q

Low frequency = contrast

High frequency = contrast

A

Good

Bad

40
Q

RIS

A

Radiology info system

Patient Health records/data

41
Q

The higher the frequency the greater the

A

Blur

Radiology Bushong (11 decks)

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