Image Production- Part 1 Flashcards
Receptor Exposure?
Density-Blackness
Contrast?
Shades of Gray
Primary Controlling Factor for Contrast?
KVP
When kVp goes up, What happens to contrast?
Contrast goes down
When kVp goes down, What happens to Contrast?
Contrast Goes Up
Factors that affect the amount of exposure reaching the radiographic IR?
Photographic Factors
What are 2 photographic factors?
Receptor Exposure- Density (Blackness)
Contrast- Shades of Gray
Usually when receptor exposure (Density- Blackness) goes UP, What usually happens to Contrast (Shades of Gray)?
Contrast Goes Down
What are factors that affect the degree of divergence of X-ray beam and the information recorded on the radiographic IR?
Geometric Factors
What are 2 Geometric Factors?
Recorded Detail
Distortion
What is the amount of blackness or opacity of an area in a radiograph?
Radiographic Receptor Exposure (Density-Blackness)
What is the difference in densities on adjacent areas of the radiographic image?
Contrast
What type of contrast?
X-ray with black and white with a few shades of gray
High Contrast
What type of contrast?\
X-ray that contains many shades of gray
Low Contrast
High or Low Contrast?
Chest X-ray
Low Contrat
High or Low Contrast?
Extremity Images
High Contrast
When mAs goes UP, What happens to density?
Density goes UP
When mAs goes UP, What happens to Receptor Exposure?
Receptor Exposure Goes UP
What is the photographic factor for Quantity?
mAs
When SID goes UP, What happens to Receptor Exposure?
Goes DOWN- Inverse Relationship
When you double the distance- What happens to exposure?
Cuts back on exposure by 4
What is the density maintenance formula?
mAs 1/ mAs 2 = SID 1/Sid 2 Squared
What is the Photographic Factor related to Quality (Penatrability)?
kVp
When kVp goes UP, What happens to the amount of radiation reaching the IR?
It Increases
When kVp goes up by 15%, What must happen with the mAs?
Half the mAs
When kVp is decreased by 15%, What happens with the mAs?
Double the mAs
When screen speed goes UP, what happens to light?
More light is given off
When screen-speed increases, What happens to receptor exposure?
Receptor Exposure goes UP
When you have faster screens, What happens to patient dose?
Decreased Patient Dose
When you have faster screens, What happens to detail?
Decreased Detail
When you have faster screens, What happens to contrast?
Contrast goes UP
When you have faster screens, What happens to radiographic exposure (Density- blackness)?
Receptor Exposure (Density- Blackness) Goes UP
What do grids do?
Clean up Scatter
More Matter =
More Scatter
What is the formula for Grid Ratio?
Grid Ratio = Height of lead strips/ Distance between them
What is the number of lead lines per inch or cm?
Grid Frequency
When do you use a grid?
When part thickness is greater than 10 cm
When given something that is NOT a grid, What do you use?
Ex. One grid is replaced by screen speed
Use a NonGrid (1)
What is another name for mAs multiplication factor (Bucky Factor)?
Grid Ratio
Example: NonGrid = 1, 5:1 Grid = 2, etc
When you add or use a grid and no technical adjustment is made, What happens to receptor exposure?
Receptor Exposure Decreases
What is the grid factor for a NonGrid?
1
What is the Grid Factor for a 5:1 grid?
2
What is the Grid Factor for 6:1 grid?
3
What is the grid factor for 8:1 grid?
4
What is the grid factor for a 10:1 or 12:1 grid?
5
What is the grid factor for a 16:1 grid?
6
What is the grid conversion formula?
MAS 1/ mAs 2 = GCF 1/ GCF 2
When you increase from a 12:1 grid to a 16:1 grid, What happens?
Increased Patient Dose
Increased Contrast because of More Scatter Cleanup
What type of factor is Filtration?
Photographic Factor
What does Filtration do to the beam?
Hardens the beam by removing low energy photons
What does filtration reduce?
Reduces skin exposure to the patient
When adding or using filtration, What happens to receptor exposure?
Receptor Exposure Decreases (because you are taking away fro the beam- so receptor exposure goes DOWN)
When a body part is thick, What happens to beam attenuation?
Increases Beam Attenuation
When you have a thick body part, what happens to receptor exposure?
Receptor Exposure Decreases
Z=
Atomic Number
A=
Atomic Mass
When the atomic number of an object increases, What happens to beam attenuation?
Beam Attenuation Increases
When the atomic number increases, What happens to radiographic exposure?
Radiographic Exposure Decreases
What is the comparison of the receptor exposure of an object to water?
Specific Gravity
When Specific Gravity increases, What happens to Attenuation?
Attenuation Increases
When Specific Gravity increases and attenuation increases, What happens to receptor exposure?
Decreases
What do additive diseases do to attenuation?
Increase beam attenuation
What do additive diseases do to radiographic exposure?
Decrease Radiographic Exposure
What do destructive diseases to to attenuation?
Decrease Beam Attenuation
What do destructive diseases do to radiographic exposure?
Increase Radiographic Exposure
What is another name for collimation/shielding?
Beam Restriction
When you remove scatter, What happens to receptor exposure?
Goes Down
When you have less tissue being exposed, You have Less?
Fog
What is the formula used for adding or removing a Grid?
GCF = mAs with a Grid/ mAs without a Grid
What is the formula for Changing Grid Ratio?
MAS 1/ mAs 2 = GCF 1/ GCF 2
When you use beam restriction (collimation), The field size?
Decreases (Less Scatter- FOG)
When you use beam restriction (collimation/shielding), What happens to radiographic exposure?
Decreases Radiographic Exposure and Reduces Scatter (Better Contrast)
What is the difference between cathode and anode?
45%
What is differences in the shades of gray?
Contrast
What is the only factor that affects receptor exposure?
mAs (only thing mAs affects)
Subject Contrast is affected by?
kVp
What is the variations in absorbing ability of objects within that part of interest?
Subject Contrast
