Image Production Flashcards
The overall amount of x-rays to reach the IR
Receptor Exposure
The quantity of x-rays to reach the IR
Receptor Exposure
The main controlling factor of receptor exposure?
mAs
The relationship between mAs and receptor exposure
Directly proportional
Increase mAs, what happens to receptor exposure?
Increase receptor exposure
Double receptor exposure
What happens if you double the mAs:
Double Receptor Exposure
The difference in adjacent areas:
Contrast
kVp is the main controlling factor of:
subject contrast
The main controlling factor of image contrast:
LUT (look up table)
The relationship between kVp and contrast is:
Inversely Proportional
If you increase kVp, contrast:
decreases
The relationship between mAs and receptor exposure:
Directly Proportional
The main controlling factor of receptor exposure:
mAs
If you increase mAs, contrast:
NO EFFECT
Increase SID, receptor exposure:
Decrease
The relationship between receptor exposure and SID?
Inversely proportional
Increasing SID, contrast:
no effect
Increase the kVp, receptor exposure:
increases
kVp and receptor exposure:
Direct Relationship
increase kVp, contrast:
decrease contrast
The relationship between kVp and contrast:
Inversely Proportional
Devices used to clean up scatter radiation
Grids
The purpose of a grid:
clean up scatter radiation
The use of a grid or an increase in grid ratio
Receptor Exposure Decreases
The relationship between a grid and receptor exposure?
Inverse Relationship
Beam Filtration:
Hardens the beam, removes soft x-rays, increase quality, decrease quantity
When you use beam filtration:
decrease receptor exposure and decrease in contrast
How tightly compacted at the atomic level:
Subject Density
List in order from least to greatest attenuation:
Air
Fat
Water
Muscle
Bone
List in order from greatest to least attenuation:
Bone
Muscle
Water
Fat
Air
What kind of kVp do you use on a mammogram?
25-30 kVp
What would you do for the kVp for the soft tissue examination of the neck?
Drop it
When things have the same rate of attenuation:
Drop the kV
Maximal Differential Absorption
Responsible for the blacks and whites on an image:
Photoelectric Effect
Why is air dark and black on an image?
Shows a high rate of radiation reaching the IR, less attenuation
Why is bone white and opaque on an image?
Shows a great rate of absorption, more attenuation
Bone is white shows:
high rates of absorption
low rates of radiation reaching the IR
As subject density increases:
decrease in receptor exposure
Increase in contrast
If you have additive pathology:
Receptor exposure decreases
Contrast Increases
When additive pathology presents:
Decrease in receptor exposure
Increase in contrast
If you have a destructive pathology:
Increase in receptor exposure
Decrease in contrast
If you increase beam restriction
decrease in receptor exposure
increase in contrast
Increase field size:
increase in receptor exposure
decrease in contrast
Misrepresentation
Distortion
What factors effect size distortion:
SID
OID
Shape distortion:
Foreshortening and Elongation
Increase SID, magnification
decreases
Why do you do the PA chest at 180 cm?
to reduce heart magnification
Increase SID
decrease magnification
increase spatial resolution
Increase in OID:
increase in magnification
decrease in spatial resolution
Which one has the greatest effect upon magnification SID or OID?
OID
*For every 1 inch of OID increase the SID to counteract magnification:
7 - 8 inches
Increase in SID:
decrease in magnification
Increase in OID:
Increase in magnification
If you increase focal spot size from a small to large:
decrease in spatial resolution
If motion is present on an image compromises:
spatial resolution
If there is ever motion on an image, what do you do as a technologist?
REPEAT the image
As a technologist, if you forget to angle the tube for an AP axial of the sacrum come in perpendicular the resulting image shows:
Shape Distortion
What factors effect spatial resolution:
SID
OID
Focal Spot Size
Motion
Material
What factors effect spatial resolution:
Geometric Factors
The number of rows times the number of columns:
Matrix
More rows and more columns. increase in matrix size:
Increase in spatial resolution
Better Pixel Coverage
Increase in pixel size:
decrease in spatial resolution
As PSP plate sizes increases:
spatial resolution decreases
The main controlling factor of spatial resolution is:
Sampling Frequency
The
The laser will scan the imaging plate and the more pixels the laser scans the greater the spatial resolution
Sampling Frequency
Increase in sampling frequency, spatial resolution:
increases
What is the main controlling factor of spatial resolution:
Sampling Frequency
OR
Focal Spot Size
As the FOV increases for a fixed matrix size:
Spatial Resolution Decreases
Increase in Flat Panel DEL:
Increase Spatial Resolution
The overall amount of radiation reaching the IR:
Receptor Exposure
The difference in adjacent areas:
Radiographic Contrast
The main controlling factor of subject contrast:
kVp
The main controlling factor of image contrast:
LUT
If an image has high contrast:
more blacks and whites
If an image has low contrast:
lots of shades of grays
The main controlling factor of receptor exposure:
mAs
The relationship between receptor exposure and mAs:
Directly Proportional
The receptor exposure on a radiograph is proportional only to the total energy imparted to the radiographic image receptor:
The Law of Reciprocity
If you get a separate mA and time in a question multiply the two out and look for the answer that matches up with it: mA x time 45 mAs
C. matches up to 45 mAs
Intensity is inversely proportional to the square of the distance:
Inverse Square Law
Recorded Detail
Spatial Resolution
If distance is doubled, intensity
4 xs less
If you cut the distance in half:
4 xs more
Mas1/mas2 = SID1^2/SID2^2
Direct Square Law
What new mAs would be used to maintain:
Direct Square Law
Room for error, that will still yield this image quality
Wide Latitude
20 mAs, 100 mA?
100/20= .2 seconds
200 ms
If you increase or decrease the kVp by 15%:
Double or cut the receptor exposure in half
Double receptor exposure by using the 15% kVp rule, 80 kV at 30 mAs?
80 x .15= 12
80 + 12 = 92 kVp
DO NOT TOUCH THE mAs
92 kVp, 30 mAs
Cut the receptor exposure in half by applying the 15% rule, 80 kV at 30 mAs:
68 kVp, 30 mAs
DO NOT TOUCH mAs
The receptor exposure is sufficient but the contrast needs to be increased, 80 kVp, 30 mAs:
68 kVp, 60 mAs
The receptor exposure is sufficient but the contrast needs to be decreased, 80 kVp, 30 mAs:
92 kVp
15 mAs
It is determined that an underexposed abdominal radiograph needs to be repeated with exposure factors doubled. If the original exposure factors were 70 kVp and 32 mAs, what new kVp should be used to improve this radiograph?
81 kVp, 32 mAs
Grid Ratio=
H (height)/D (distance)
The height of lead strips, width (not use), width of interspace (use):
H/D
A radiographic examination is performed 80 kV, 10 mAs, 100 cm SID with a 5:1 grid ratio, a new exposure is made with a 16:1 grid ratio to increase contrast, what is the new technique?
5:1 (2)
16:1 (6)
old mAs/new mAs= old grid/new grid
An AP knee radiograph is performed at 60 kVp and 3 mAs on a 400 speed class IR. What new mAs is needed if going to a 8:1 grid?
3/x = 1/4
x= 12 mAs
Need at least _______ grid frequency to prevent the Moire Effect.
60 lines/cm
A measure of Grid lines per unit distance:
Grid Frequency
What is the purpose of filtration:
Reduce the ESE
As thickness increases, beam attenuation __________, and receptor exposure __________.
increases, decreases
As the atomic number of an object increases attenuation will _______ yielding a _________ in radiographic exposure.
increase, decrease
Increase field size, _________ receptor exposure
increase
Collapsed Lung
Atalectasis
Abdominal Fluid
Acities
Forward displacement on one vertebrae on top of the other vertebrae
Spondylotisthesus
A patient presents in the ED department fever, shortness of breath, cough:
Pneumonia
Pnuemonic Infiltrate
A patient presents in the ED, dipheretic, cool, clammy, cold to touch, fever, shortness of breath:
Congestive Heart Failure
AP T-spine where do you place the cathode?
lower T-spine, anode- over the upper T-spine
On all extremities place the cathode:
over the proximal joint
For the thoracic and abdominal cavity put the cathode:
On the diaphragm
On a lateral T-spine on an average T-spine requires:
Lateral
AP
Laterocervical thoracic
On a lateral T-Spine the put the cathode:
UP on the upper T-spine
Short-Scale Contrast:
Black and White Appearance
Intrathecally:
within the spinal canal
Increase kVp ________ contrast
decrease
The three things that effect the production of scatter:
high kVp
Large thick parts
Large Field Sizes
All of the following effect the production of scatter except:
Grid
With the use of filtration the beam is:
more homogenous
The clear consice center:
Umbra
The pneumbra aka the geometric unsharpness is always greater on the:
Cathode Side of the Beam
Bluring around the edges
Geometric unsharpness
Image size/object size= SID/SOD
Magnification
The heart on the IR measures 15.2 cm at the widest point, in the chest cavity is only 6.2 cm. How much magnification?
15.2 cm/6.2= 2.45
A radiographic examination is performed with 180 cm SID, but the anatomical part has a 20 cm OID. How much magnification?
180/160= 1.125
180-20= 160
What is the best way to control voluntary motion?
clear concise instruction
What is the best way to control involuntary motion?
Shorter Exposure Times
Respiration, peristalsis, cardiac activity, parkinson’s disease:
Involuntary
The main controlling factor of spatial resolution?
Focal Spot Size
Where the electrons actually strike the target:
Actual Focal Spot
What gets projected down onto the patients:
Effective Focal Spot
Which is larger the actual or effective?
Actual Focal Spot
Which of the following anode angles gives me the greatest spatial resolution?
Smaller the angle the greater the spatial resolution
Pick the smallest number
If you are going to do a hand x-ray table top, is the hand x-ray the use of an APR or the use of an AEC?
APR
