Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/58

Click to flip

58 Cards in this Set

  • Front
  • Back

misrepresentation of an anatomic structure on an image receptor (size and shape) is known as

distortion

the sharpness of anatomic structures displayed on an image receptor is the

recorded detail

the overall blackness of the image is the

density (mAs)

the difference between adjacent densities on a radiograph is the

contrast

recorded detail (overall sharpness) depends on what 4 factors

-oid


-sid


-fss


-screen speed

distortion (misrepresentation) depends on what 3 factors

-oid


-sid


-tube/part/film alignment

mAsdn is an acronym for what rule

mAs controls film density

KCCL represents what rule

Kvp


Controls


Contrast


quaLity

T/F: a significant amount of mAs will compensate for a lack of kVp

FALSE!! mAs controls the overall darkness; kVp will control the penetrability, therefore, mAs will not increase the energy of the beam

high kV will carry long/short wavelengths

short (more energy, which means higher frequency or more wavelengths in a sec)

a high kV carries a long/short scale of contrast

Long; many shades of gray


B///////////////////////////W

a high kV has a wide/narrow latitude

wide latitude

what type of radiation exits the patient and carries the information to the film

remnant radiation

the invisible image on film after exposure/before processing is

latent image

visible image on film after processing is the

manifest image

what are the 2 components of recorded detail (aka resolving power)

-contrast resolution


-spatial resolution (lp/mm)

spatial resolution refers to

how small an object can be imaged

Very fast screens carry lp/mm of

7

direct exposure film has how many lp/mm

50

as intensification factor increases, spatial resolution will

decrease

on which end of the tube is penumbra greatest

cathode end; place thickest part under the cathode end (known as Heel Effect or FATCAT)

Better detail occurs under which end of the tube

Anode; place area of interest under anode to see better detail

3 Factors of unsharpness (mgm)

-motion


-geometry (measurable)


-materials (measurable)

4 methods to reduce exposure time

-mA/time relationship


-kVp/mAs rule


-screen speed


-SID

3 Factors of material unsharpness are

-Film/screen contact (most intrisitic)


-Screen use


-Film used

This evaluates a system's ability to record an extremely narrow beam slit of 10 microns wide

Line Spread Function

Ideal film screen contact includes this

Absolute contact/complete contact

Where is unsharpness evident on the film

Only in the immediate area of the poor contact

Inherent unsharpness with screens formula

old sharpness X pc^2

Material Unsharpness of slow screens is

0.25 mm

material unsharpness of par screens is

0.35 mm

material unsharpness of high screens is

0.45 mm

material unsharpness of rare earth screens is

0.55 mm

more/less xray photons needed for adequate density w/ screens

less

more/less radiographic technique needed w/ screens

less

more/less dose to the patient w/ screens

less

worse/better resolution w/ screens

worse

more/less contrast w/ screens

more

wide/narrow exposure latitude (gray tones) w/ screen

narrow (fewer gray tones/increased contrast)

any material that emits light in response to some outside stimulation is called

luminescence or a phosphor (screen characteristic)

Luminescence involves ______ of outer shell electrons' energy levels

excitation

2 types of luminescence are

-fluoro (light emitted within 10^-8 sec)


-Phosphor (light emitted beyond) aka screen lag or afterglow ADDS DENSITY

Speed screens range from _____ to _____

50 to 1200, w/ par being 100

As speed increases, detail will

decrease

Intensification factor will _____ as kVp rises

increase

As phosphor size and layer thickness increases, detail and dose will

decrease

As phosphor size and layer thickness increases, film density will

increase

If the anode bevel angle is less than 45 degrees, the EFSS is ____ than the actual FSS

smaller (line focus principle)

This is a problem which may arise from increasing mA applied to the tube; loss of image resolution; very little significance, but occurs in angography

Blooming of Focus

absorption of the xrays or a reduction in the amount as they pass through matter is known as

attenuation

what 2 factors determine attenuation

-z number


-tissue density

atomic number of bone is

13

atomic number of soft tissue is

about 6

A high Z number, such as bone, will appear

radiopaque (white)

secondary and scattered radiation produces ____ on the radiograph

fog

when kV is increased, the wavelength will increase/decrease allowing more radiation to go through the body

decrease

short scale contrast has ___ grays, ____ contrast, produced w/ ____ kV, and w/ ____wavelengths

-few grays (narrow latitude)


-high


-low kV


-increasing wavelengths

exposure or intensity is controlled by

mAs