Image Quality Flashcards
Thoracic view:
1. Standard to include…
2. Goal
3. Center
- Standard to include:
- Thoracic inlet to the last rib (or 6th rib) - Goal:
- Assess the lung fields
- Tech should allow visualization of major blood vessels and airways to the lungs - Center:
- Over the heart
Abdominal view:
1. Standard to include…
2. Goal
3. Center
- Standard to include:
- Diaphragm to guarantee all of the liver in view and include pelvic canal/hip joint to visualize bladder and colon when possible - Goal:
- Ask DVM! - Center over 13th rib
What does a “Met Check” include?
Includes both lateral and a VD view of the thorax
Pelvis Lateral:
1. Standard to…
2. Goal
3. Center
- Standard to ask DVM if legs should be scissored or superimposed
- Goal:
- Include all pelvis and proximal 1/3 of femur - Center:
- Point of the femur
Limbs:
1. Standard to include…
2. Goal
3. Center
What is LEGALLY needed on a radiograph label? (4)
- Owners name
- Animals name
- Clinic name or DVM
- Exam date
What does not need to be on a radiograph image but is beneficial? (6)
- Signalment
- Region imaged
- Tech initials/name
- View labels (R, L, DV, CrCd)
- Limb labels
- Time clocks/image #
What are three goals when it comes to positioning for standard views?
- Area of interest directly in center of primary beam, this minimizes size/shape distortion
- Area of interest parallel to cassette/table and perpendicular to beam, this minimizes distortion
- Area of interest touching cassette/table, this minimizes magnification and increases details
Lateral view GOALS (3)
- All chest structures should be parallel to the table. You may need a sternal wedge
- Ribs should superimpose each other. Thoracic vertebrae should appear to have one rib head
- Transverse processes of vertebrae are super imposed - Take at peak inspiration
- Space between heart and diaphragm - Structures of shoulder should not overly the lung and heart
DV or VD GOALS (2)
- Structures within the chest should be parallel to table
- Sternum and spine should superimpose
- Dorsal spinous processes align, centered over vertebral bodies
- Structures of shoulders shouldn’t overly lungs - Peak inspiration
- Space between heart and diaphragm
Resolution problems: Non-digital related errors (6)
- Motion of patient
- Fog due to scatter
- Noise due to overexposure
- Drop out due to overexposure
- Double exposures
- Gird cut off/improper use of grid
An image that is too dark is:
a. Overexposed
b. Underexposed
Overexposed
An image that is too light is:
a. Overexposed
b. Underexposed
Underexposed
Resolution problems: Digital artifacts (5)
- Look-up table/image processing errors
- Exposure artifacts
- CR & DR artifacts
- Interference artifacts
- Display artifacts
T/F: mAs is how many photons are being thrown to the image
True
T/F: kVp is how “fast” the photons are being thrown
True
Exposure artifact:
What can extreme levels of exposure result in?
Very high levels of exposure can result in saturation
- Max detector response is reached
- No response to increased dose
- Uniformly dark portions or anatomy disappear in a “band”
- Cannot be windowed or levelled
ALARA meaning
As Low As Reasonably Achieved principle
Dynamic Range (3)
- Underexposure to the IP (image processer) results in an increases in Quantum mottle or noise.
- It is the responsibility of the radiographer to choose the best technique
suitable for producing an optimal image. - A.L.A.R.A principle. (As low as reasonably achievable)
Exposure indicators (EI) at BTC lab
1. Konica system uses…
2. ‘0’ represents extreme ___ exposure while ‘2000’ is ____ exposure
3. Optimal range is ____ with ___ being too dark and ___ being too light
4. Ideal exposure is ____
- Uses inversely proportional number system from 0 to 2000
- over exposure; no detectable exposure
- Optimal is 200-400. 200 being too dark and 400 too light
- Ideal exposure is 200
T/F: In digital changing the mAs will have little effect on the image quality
False. The mAs will have the GREATEST effect on image quality.
You must double the mAs or reduce by half for significant effects
Brightness controls…
Contrast controls…
- How light or dark the image is
- How many shades of gray are in the image
